PURPOSE: To provide a pattern generation system capable automatically generating patterns for the supplements of solid patterns to a solid pattern disapproval area.

CONSTITUTION: This system is provided with a pattern data base 1 for storing circuit design patterns, a control part 2 for controlling pattern generation based on the circuit design patterns read from the pattern data base 1, a graphic display 3 for displaying the process of the pattern generation and a memory 4 for storing the various kinds of data, and a grid line segment table 10 for storing grid patterns for the supplements to the solid pattern disapproval area as grid line segments is provided inside the memory 4.