To simplify the structure of a dresser device to perform dressing of a grinding wheel, heighten the rigidity of the dresser to prevent chattering at the time of dressing, and shorten the time for dressing operation.

A rotary dresser 35 of a dresser device 30 is arranged as merely rotating in the specified fixed position and is located behind a grinding wheel 3 which advances relative to a work W held on a spindle stock 14 and performs grinding, and contacting with the rotary dresser 35 is generated when the grinding wheel 3 is moved backward in the direction of going apart from the work, and thus dressing is conducted. Because of this structure of dresser device 30 in which the rotary dresser 35 is merely held rotatably in the specified fixed position, the configuration remains simple and the shaft to retain the dresser 35 can be thickened to lead to establishment of a heightened rigidity.