A soft wheat flour, Tokutakaragasa (protein 9.69 %), was dry-heated at 120℃ for 10, 20, 30, 60, and 120 minutes, and baked into Kasutera cakes (Japanese sponge cakes). The volume of Kasutera cake increased with duration of dry heating. Also, the stability of foam in Kasutera cake batter increased with the dry-heating time of wheat flour. The mixograph profile of dry-heated wheat flour also suggests the hydrophobicity of wheat flour. Thus, the results suggest that the hydrophobicity of the dry-heated wheat flour could stabilize the foam in Kasutera cake batter and contribute to increasing Kasutera cake volume.