A temperature adjustment device 10 includes a PID calculation part 12 for calculating a PID value, a PID control part 14, and a determination part 15. The PID control part 14 performs PID control and calculate an amount of manipulation for a control target using the PID value, a target value of the control target, and an actually measured value of the control target. The determination part 15 determines whether or not to stop calculation of the PID value using a combination of the target value and the actually measured value or the PID value. This suppresses control performance degradation of PID control.