In a Stirling refrigerator, a regenerator has a low-temperature end and a high-temperature end. A plurality of protrusions, which thermally contact with the low-temperature end of the regenerator, are formed on a low-temperature heat exchanger. The low-temperature heat exchanger has a recess between the protrusions, and the recess forms a flowing groove through which a working gas flows. The regenerator may contain a mesh regenerator material.