PURPOSE: To enable more delicate editing work according to a user and a programming language by incorporating a user-defined editing function into an editor program.

CONSTITUTION: A user edit definition area 1a is secured in a pre-incorporation editor program 11, and a user-defined editing program 12 which demonstrates user-specific editing functions at an execution time is, by using the pre- incorporation editor program 11, generated by a user, and an editor incorporation utility program 13 incorporates the user-defined editing program 12 into the user edit definition area 11a of the pre-incorporation editor program 11 so as to generate a after-incorporation editor program 10.