A pattern correction method executed by a computer includes a first correction and a second correction. The first correction is executed by calculating a correction value, in consideration for an optical proximity effect, for edges (first edges) meeting a condition among the edges constituting a designed pattern. Subsequently, The second correction is executed for an edge (second edge) which does not meet the condition, by use of the correction value of any one of the edges (first edges) adjacent to the second edge among the first edges for which the first correction is executed, thus connecting the corrected first edge and the corrected second edge by a line segment. The pattern is corrected to a shape suitable for a mask drawing and a check with simple processing.