PURPOSE: To avoid a steep rise of temperature even when fresh air mixes into a freezing chamber.

CONSTITUTION: A stirling engine 1 produces cold heat with a heat cycle process at least including an expansion process of working gas fed into an expansion chamber 5 formed at a destination part of an expansion cylinder part 4a from a compression chamber 3 formed at a destination part of a compression cylinder part 2a. A heat conduction part 18 transmits cold heat produced in the expansion chamber 5 formed at the top end of the expansion cylinder part 4a connected to the expansion chamber 5. A freezing box 10A has an inner wall 12 covered with a heat conductive plate and forms therein a freezing chamber 15 for accommodating a freezing load, and further includes a heat conductive part 18 protruded in the freezing chamber 15 and a placement shelf for placing a freezing load.