PURPOSE: To provide a production plan making device which can debug the knowledge needed for making a production plan in a simple way and also can change and correct the production plan.

CONSTITUTION: A plan knowledge base 2 stores the resources and parameters of a plan making system and the plan making knowledges. These knowledges are divided into the allocation knowledge, the procedure knowledge, and the limit knowledge by a knowledge editor 1. These divided knowledge are related with each other and then edited and stored. A precondition can be added to each knowledge. A plan making means 4 refers to the knowledges, etc., stored in the base 2 to make a production plan. Then the production plan is stored in an allocation data base 6 and also shown on a display means 5. Furthermore a user can change the production plan made by the means 4 to control the plan by a user intervention means 3.