PURPOSE: To provide a rotary grinding machine capable of performing truing and dressing of a grinding wheel using truing grinding wheels.

CONSTITUTION: A truing device 31 is loaded on the upper face of a saddle 2 so that truing grinding wheels 35, 36 can reciprocate in a direction that intersects the direction of movement of the saddle 2 at right angles. Thus, the truing grinding wheels 35, 36 can be reciprocated in a direction that intersects the axis-line of rotation of a grinding wheel 21 at right angles. As a result, the grinding efficiency of the grinding wheel 21 can be improved, and the peripheral grinding surface of the grinding wheel 21 can be formed with high precision.