A cylinder assembly of a hermetic compressor has a valve plate disposed on an outer side of a cylinder block to cover an open side of a cylinder, the valve plate defines a refrigerant discharge hole therethrough which is adapted to discharge a compressed refrigerant from the cylinder. A cylinder head disposed to cover the outer side of the valve plate defines a refrigerant discharge chamber in cooperation with the valve plate. A discharge valve is disposed between the valve plate and the cylinder head in a cantilever fashion with a central portion thereof covering the refrigerant discharge hole. A restricting mechanism comprising a first stopper member protruding from an inner wall of the cylinder head a distance such that a terminal edge of the first stopper member is at a predetermined distance from a free end of the discharge valve for restricting movement of the discharge valve. During the opening of the refrigerant discharge hole, the discharge valve is deformed such that the central portion deformed toward said cylinder head while movement of the free end of the discharge valve limited due to the first stopper member.