A temperature measuring apparatus includes: an infrared measuring unit; a guide light emitting unit; an optical unit that (i) allows the guide light emitted by the guide light emitting unit to travel toward the object, and (ii) allows the infrared radiation radiated from the object to enter the infrared measuring unit; a position adjusting unit that makes a position adjustment of irradiating the measurement target region with the guide light emitted by the guide light emitting unit while keeping within a predetermined range a misalignment between an optical axis of the infrared radiation entering the infrared measuring unit from the measurement target region and an optical axis of the guide light emitted by the guide light emitting unit; and a focusing unit that adjusts a focus of the infrared measuring unit and a focus of the guide light emitting unit.