A temperature detection device that detects a temperature of a rotor of a motor. The temperature detection device has a current detection unit configured to detect a current value of a current flowing through a winding with which any one of a stator and the rotor of the motor is provided, an iron loss estimation unit configured to estimate an iron loss of the rotor using the current value, and a rotor temperature estimation unit configured to estimate the temperature of the rotor using the iron loss.