A Stirling engine, wherein the inner yoke of a linear motor is installed on the outer peripheral surface of a cylinder. To keep a proper pressure balance between a compression space on one end side of a displacer and a back pressure space on the outer peripheral side of the cylinder, a first flow passage is formed in the piston starting at the compression space side end face toward the outer peripheral surface and a second flow passage allowing the first flow passage to communicate with the back pressure space is formed in the cylinder. The second flow passage is composed of a through hole that penetrates the wall of the cylinder in a radial direction and a communication passage formed between the outer peripheral surface of the cylinder and the inner peripheral surface of the inner yoke to allow the through hole to communicate with the back pressure space.