Rotary valve unit in a pulse tube refrigerator

A rotary valve unit in a pulse tube refrigerator is quiet, and has high durability and improved refrigeration efficiency by restricting the generation of unidirectional flow. A center hole is formed on a sliding plane side as a recessed space in the sliding surfaces between the sliding plane and another sliding plane. Since the second center hole is in communication with a low pressure input port via a communication passage, the leakage between the sliding surfaces of the sliding planes can be introduced to the low pressure input port with low pressure.