Provided is a gear grinding method capable of improving processing accuracy and easily adjusting the crowning shape by simplifying a processing operation. To this end, a work piece (W) is ground by a gear-shaped grinding stone (11) having a drum shape such that crowning along a tooth trace direction is applied to the work piece (W) by applying a relative feed in a feed direction (D1) that intersects a work piece rotation axis (C1) at a predetermined first diagonal angle (θ1) between the work piece (W) and the gear-shaped grinding stone (11) while the work piece (W) and the gear-shaped grinding stone (11) are synchronously rotated in the state of being engaged so as to have a predetermined crossed axes angle (Σ), and the curvature in a grinding stone width direction, which defines the drum shape of the gear-shaped grinding stone (11), and the first diagonal angle (θ1) are set according to the crowning shape of the work piece (W).