PURPOSE: To prevent the contact of the tip of a spindle housing with a work and a chuck table at the time of cutting the work by installing a small diameter blade in the tip of a narrow extension part in a flange for small diameter blade of a dicing device.

CONSTITUTION: A flange 3 for small diameter blade, which is to be fitted to a spindle 2 projected from a spindle housing 1, has a cap-shape spindle installation part 3a and a narrow extension part 3b extended from the spindle installation part 3a. The tip of the extension part 3b is formed with a stage part 3d (small flange) for receiving a small diameter blade 4, and the tip of this stage part 3d is formed with a screw part 3e. After pinching the small diameter blade 4 with an annular presser small diameter flange 6 and the surface of the stage part 3d, a small diameter fastening nut 7 is threaded with the screw part 3e so as to fix the small diameter blade 4.