A motor controller includes memory, and processing circuitry that controls a motor based on a position command and based on a position detection value corresponding to a detected position of the motor, calculates a tolerance position error in a successive manner based on the position command and based on a control parameter used to control the motor, calculates a position error maximum threshold that depends on the tolerance position error, detects an abnormality based on the position error maximum threshold, and triggers an indication when the abnormality is detected.