Provided is a contact type internal thermometer including: a measurement surface that is brought into contact with a surface to be measured of a measurement object a first temperature sensor stack including a first measurement surface side temperature sensor arranged on a measurement surface side, and a first back surface side temperature sensor arranged on a back surface side a second temperature sensor stack including a second measurement surface side temperature sensor arranged on a measurement surface side, and a second back surface side temperature sensor arranged on a back surface side and a controller configured to calculate an internal temperature of the measurement object based on measurement results of the respective temperature sensors, in which the first back surface side temperature sensor and the second back surface side temperature sensor have different surface areas.
