A mask pattern generation method of generating a mask pattern from a designed pattern, comprising preparing the designed pattern, preparing a correction parameter, preparing a first correction library in which a plurality of pairs of an edge coordinate group and a correction value group to correct the edge coordinate group is registered, acquiring edge coordinate groups of the designed patterns, generating a second correction library in which only the plurality of pairs of an edge coordinate group agreeing with the acquired edge coordinate group and the correction value group is registered in the first correction library and simulation using the correction parameter, and correcting the designed pattern using the second correction library.