A speed controller for motor comprising a speed control section for generating an original current command based on the difference between a detected speed of a motor for driving a load and a speed command of the motor, a notch filter for cutting off a notch frequency becoming a selected specific frequency out of a continuous frequency band width and generating a compensation current command by removing the notch frequency from the original current command, a notch filter adaptive section for selecting the notch frequency such that a compensation current command from which the sustained oscillation frequency component of the original current command is removed is generated from the notch filter, a subtrator generating a removal current command becoming the difference between the original current command and the compensation current command, and an adder generating a current command being fed to the motor by adding the compensation current command and the removal current command.