A device includes: an ultrasonic wave irradiation unit that irradiates a living body with an ultrasonic wave; an ultrasonic wave detection unit that receives an ultrasonic wave reflected by the living body; and a calculation unit that calculates an amount of temperature change in the living body. The calculation unit is configured to: calculate a frequency of an ultrasonic wave amplified in the living body, based on information on a structure of the living body; perform frequency analysis on the ultrasonic wave received by the ultrasonic wave detection unit and acquire an amplitude spectrum of the ultrasonic wave; identify, from the amplitude spectrum, a peak frequency closest to the frequency of the ultrasonic wave; calculate an amount of frequency change, from two peak frequencies identified by ultrasonic wave irradiations in twice; and calculate an amount of temperature change in the living body from the amount of frequency change.