Abstract: There is disclosed a gear cutting method for cutting a work by a milling cutter of a gear cutting planar having a cutting blade formed in a shape similar to involute curve. It comprises setting the work on a table intermittently rotating on a bed of a main body of the gear cutting planar, measuring and obtaining a heat expanding amount of the work in advance, compensating the feeding amount and the processing pitch of the milling cutter according to expanded dimension of the work at the time when the work is expanded by cutting heat, and cutting the work from a lower part to an upper part thereof by the milling cutter.