diff --git a/erpnext/manufacturing/doctype/bom/bom.py b/erpnext/manufacturing/doctype/bom/bom.py
index 2cd8f8c15a..f82d9a0d55 100644
--- a/erpnext/manufacturing/doctype/bom/bom.py
+++ b/erpnext/manufacturing/doctype/bom/bom.py
@@ -922,7 +922,7 @@ def validate_bom_no(item, bom_no):
 				rm_item_exists = True
 		if bom.item.lower() == item.lower() or \
 			bom.item.lower() == cstr(frappe.db.get_value("Item", item, "variant_of")).lower():
- 				rm_item_exists = True
+				rm_item_exists = True
 		if not rm_item_exists:
 			frappe.throw(_("BOM {0} does not belong to Item {1}").format(bom_no, item))
 
diff --git a/erpnext/manufacturing/doctype/bom_operation/bom_operation.json b/erpnext/manufacturing/doctype/bom_operation/bom_operation.json
index ec617f3aaa..c7be7efc9e 100644
--- a/erpnext/manufacturing/doctype/bom_operation/bom_operation.json
+++ b/erpnext/manufacturing/doctype/bom_operation/bom_operation.json
@@ -11,6 +11,7 @@
   "col_break1",
   "workstation",
   "time_in_mins",
+  "fixed_time",
   "costing_section",
   "hour_rate",
   "base_hour_rate",
@@ -79,6 +80,14 @@
    "oldfieldtype": "Currency",
    "reqd": 1
   },
+  {
+   "default": "0",
+   "description": "Operation time does not depend on quantity to produce",
+   "fieldname": "fixed_time",
+   "fieldtype": "Check",
+   "in_list_view": 1,
+   "label": "Fixed Time"
+  },
   {
    "fieldname": "operating_cost",
    "fieldtype": "Currency",
@@ -177,12 +186,13 @@
  "index_web_pages_for_search": 1,
  "istable": 1,
  "links": [],
- "modified": "2021-09-13 16:45:01.092868",
+ "modified": "2021-12-15 03:00:00.473173",
  "modified_by": "Administrator",
  "module": "Manufacturing",
  "name": "BOM Operation",
  "owner": "Administrator",
  "permissions": [],
  "sort_field": "modified",
- "sort_order": "DESC"
+ "sort_order": "DESC",
+ "states": []
 }
\ No newline at end of file
diff --git a/erpnext/manufacturing/doctype/work_order/test_work_order.py b/erpnext/manufacturing/doctype/work_order/test_work_order.py
index 165e0acebb..86c687fb7c 100644
--- a/erpnext/manufacturing/doctype/work_order/test_work_order.py
+++ b/erpnext/manufacturing/doctype/work_order/test_work_order.py
@@ -846,6 +846,45 @@ class TestWorkOrder(ERPNextTestCase):
 			close_work_order(wo_order, "Closed")
 			self.assertEqual(wo_order.get('status'), "Closed")
 
+	def test_fix_time_operations(self):
+		bom = frappe.get_doc({
+			"doctype": "BOM",
+			"item": "_Test FG Item 2",
+			"is_active": 1,
+			"is_default": 1,
+			"quantity": 1.0,
+			"with_operations": 1,
+			"operations": [
+				{
+					"operation": "_Test Operation 1",
+					"description": "_Test",
+					"workstation": "_Test Workstation 1",
+					"time_in_mins": 60,
+					"operating_cost": 140,
+					"fixed_time": 1
+				}
+			],
+			"items": [
+				{
+					"amount": 5000.0,
+					"doctype": "BOM Item",
+					"item_code": "_Test Item",
+					"parentfield": "items",
+					"qty": 1.0,
+					"rate": 5000.0,
+				},
+			],
+		})
+		bom.save()
+		bom.submit()
+
+
+		wo1 = make_wo_order_test_record(item=bom.item, bom_no=bom.name, qty=1, skip_transfer=1, do_not_submit=1)
+		wo2 = make_wo_order_test_record(item=bom.item, bom_no=bom.name, qty=2, skip_transfer=1, do_not_submit=1)
+
+		self.assertEqual(wo1.operations[0].time_in_mins, wo2.operations[0].time_in_mins)
+
+
 def update_job_card(job_card):
 	job_card_doc = frappe.get_doc('Job Card', job_card)
 	job_card_doc.set('scrap_items', [
diff --git a/erpnext/manufacturing/doctype/work_order/work_order.py b/erpnext/manufacturing/doctype/work_order/work_order.py
index 0090f4d04e..170454c823 100644
--- a/erpnext/manufacturing/doctype/work_order/work_order.py
+++ b/erpnext/manufacturing/doctype/work_order/work_order.py
@@ -505,16 +505,19 @@ class WorkOrder(Document):
 		"""Fetch operations from BOM and set in 'Work Order'"""
 
 		def _get_operations(bom_no, qty=1):
-			return frappe.db.sql(
-					f"""select
-						operation, description, workstation, idx,
-						base_hour_rate as hour_rate, time_in_mins * {qty} as time_in_mins,
-						"Pending" as status, parent as bom, batch_size, sequence_id
-					from
-						`tabBOM Operation`
-					where
-						parent = %s order by idx
-					""", bom_no, as_dict=1)
+			data = frappe.get_all("BOM Operation",
+					filters={"parent": bom_no},
+					fields=["operation", "description", "workstation", "idx",
+						"base_hour_rate as hour_rate", "time_in_mins", "parent as bom",
+						"batch_size", "sequence_id", "fixed_time"],
+					order_by="idx")
+
+			for d in data:
+				if not d.fixed_time:
+					d.time_in_mins = flt(d.time_in_mins) * flt(qty)
+				d.status = "Pending"
+
+			return data
 
 
 		self.set('operations', [])
@@ -542,7 +545,8 @@ class WorkOrder(Document):
 
 	def calculate_time(self):
 		for d in self.get("operations"):
-			d.time_in_mins = flt(d.time_in_mins) * (flt(self.qty) / flt(d.batch_size))
+			if not d.fixed_time:
+				d.time_in_mins = flt(d.time_in_mins) * (flt(self.qty) / flt(d.batch_size))
 
 		self.calculate_operating_cost()