Magnetic disk apparatus includes a magnetic head element having a read element and a write element, a heater provided in the magnetic head element for controlling a protruding amount thereof, a write resistance detector that detects a resistance value of the write element, and an MPU (write element temperature calculation unit) that calculates a temperature of the write element as a temperature of the magnetic head element based on a resistance value of the write element detected by the write resistance detector and a temperature coefficient of the write element.