Provided is a method for grinding electrode tips such that the method is capable of detecting irregular grinding when the maximum torque does not occur. Specifically, a tip dresser includes a holder holding a cutter, a servo motor unit allowing the holder to rotate, and a controller controlling the operation of the servo motor unit. The servo motor unit outputs a torque occurrence signal to the controller when a load torque reaches a predetermined value in regular grinding of a pair of electrode tips. The controller detects irregular grinding when not receiving the torque occurrence signal within a time that corresponds to an elapsed time in the regular grinding.