A cryogenic refrigerator includes a cylinder configured to be fed with a refrigerant gas, a displacer configured to reciprocate in the cylinder, a drive unit configured to cause the displacer to reciprocate in the cylinder, and a connecting mechanism connecting the drive unit and the displacer. The connecting mechanism includes an output shaft extending from the drive unit toward the displacer, an engagement pin provided through the output shaft to extend in directions to cross the reciprocating directions of the displacer, a rotation prevention mechanism configured to engage with the engagement pin to prevent a further rotation of the displacer when the displacer rotates, and a lid body fixed to an end portion of the displacer and engaging with the output shaft.