To stabilize polishing quality and improve production efficiency by automatically controlling a polishing condition by a buff wheel 12.

A buff machining controller is provided with a buff drive motor 13 for rotating the buff wheel 12, a buff pressing motor 14 for giving pressing force against a workpiece W to the buff wheel 12 through a ball screw 16, a current sensor 1 for detecting load of the buff wheel 12 as a load current value, a position sensor 2 for detecting a wear amount of the buff wheel 12 as a travel amount of the buff wheel 12, and a controller 4 for controlling the drive of the buff pressing motor 14 and the buff drive motor 13 from a detected value and a reference value of the current sensor 1 and the position sensor 2.