To provide a discharge valve for a compressor, comprising a valve element for reducing tensile stress by reducing pressure difference before-and- after.

A discharge valve assembly 12 mounted in discharge passages 86, 88 between a discharge pressure area and a discharge chamber has a discharge valve element 134 permitting only the fluid flow from the discharge pressure area to the discharge chamber direction. The valve element energized by a spring 132 to adjust an out-flow port 118 of a valve plate 136, has a uniform thickness, and is specially outlined. The valve element preferably has approximately the shape of dome projecting toward the discharge pressure area to smooth the fluid flow around the valve element.