An image forming apparatus includes: a detected member of which a temperature is to be detected; a temperature sensor including a contact portion provided to contact the detected member, the temperature sensor being configured to detect the temperature of the detected member; and a condition determining unit. The condition determining unit is configured to control electric power supplied to the temperature sensor such that the temperature sensor self-heats during a heating time period, and determine a condition of the contact portion based on the temperature detected by the temperature sensor after the temperature sensor starts self-heating.