To provide a part cutting device suitable for cutting a round part with high cutting accuracy, satisfactory cutting surface, dispensing with secondary processing such a finishing.

A table 3 is provided on a base 2 of this cutting device 1. The table 3 is movable along two directions crossing on a horizontal plane. A cutting direction is in the X direction. A part rotating means 4 for holding and rotating an end of the round part 5 is mounted on the table 3. A cutting means 11 equipped with a grinding wheel 12 is mounted on the base 2. Both of a rotating shaft 15 of the grinding wheel 12 and a central axis 16 of the part rotating means 4 are horizontal, and the central axis 16 of the part rotating means 4 is placed a little lower. Not only the grinding wheel 12 but also the round part 5 rotates during cutting. Therefore, a range to be cut is larger than when only the blade rotates even if the cutting amount of the grinding wheel 12 is small. Force applied to the round part 5 on cutting is little, and therefore, a problem, such as seizing does not occur on a peripheral part opposite to a cutting side of the cutting surface.