PURPOSE: To secure such a circular saw grinder as being speedy and yet inexpensive as well as suitable for automation at shop, by rotatably supporting a grinding wheel in making it meet the specified blade to be ground of a circular saw for its rake face, flank, side rake face, etc.

CONSTITUTION: An arm shaft being an outer circumferential part of a circular saw 4 and set up in parallel with a support shaft of the circular saw 4 is installed free of rotation and adjustment centering on its shaft center via a first rotation mechanism. At the arm shaft, an arm being projected outward in a radial direction from its shaft center is locked, while a slide shaft 28 having its shaft center in the projecting direction of the arm is installed free of reciprocation and slide motion in an outer end part of the arm via a sliding mechanism. In addition, a rotary shaft 34 is installed free of rotation and adjustment centering on the shaft center via a second rotation mechanism 36, while a spindle housing 38 is locked to an end part at the circular saw side of the rotary shaft 34, and a spindle shaft 40 being orthogonal with both the support shaft of the circular saw 4 and the rotary shaft 34 is installed in this housing 38 via a driving mechanism 47 and then a grinding wheel 42 is locked to the spindle shaft 40.