A servo controller includes: a servo control unit that controls a motor in a machine based on a position command; a position detection unit that detects the position of the motor; a positional error calculation unit that calculates a positional error between the position command and the position of the motor; a position abnormality detection unit that detects a position abnormality in the motor when the positional error is a first threshold or more; a load detection unit that detects a load torque on the motor; a load abnormality detection unit that detects a load abnormality in the motor when the load torque is a second threshold or more; an abnormality detection unit that detects an abnormality in the machine when the position abnormality or the load abnormality is detected; and a threshold change unit that changes the first or second threshold in response to the load state of the motor.