An alkaline protease having an amino acid with one or more amino acid residues selected from among those located at (a) position 15, (b) position 16, (c) position 166, (d) position 167, (e) position 187, (f) position 346, and (g) position 405 of the amino acid sequence of SEQ No; 1, or at positions corresponding to these positions, are the following amino acid residues, respectively: (a): histidine, (b): threonine or glutamine, (c): glycine, (d): valine, (e): serine, (f): arginine, and (g); and a gene encoding the alkaline protease.