An electronic thermometer includes first and second body surface temperature measurement portions to measure first and second values of a measurement object, first and second reference temperature measurement portions to measure values at each position having a predetermined thermal resistance relative to a measurement position of the first and second values, and having a first and second thermal resistance relative to the open air, third temperature measurement portion to measure a third value at a different position from the previous values, correction portion to correct the obtained values; and core body temperature calculation portion to calculate a value of the object using the obtained values.