A Stirling engine includes at least a first cylinder and a second cylinder arranged in serial, and a heat exchanger. The heat exchanger includes a radiator, a regenerator, and a heater. At least a part of the heat exchanger is formed in a curved shape so as to connect between the first cylinder and the second cylinder. The heater is formed in a curved shape so as to connect between the first cylinder and the second cylinder. The radiator and the regenerator are linearly formed along the direction of extension of the cylinder.