a reciprocating compressor has a plurality of compressor stages each compressing a working gas by combining a cylinder and a plunger , and its discharge pressure exceeds 40 mpa . the compressor stage has a packing seal which seals a shaft of the plunger , and oil pouring means which pours a lubricating oil to the packing seal . a filter removes the lubricating oil poured by the oil pouring means from the working gas . in the filter , a first element using micro glass fiber and a second element using functional activated carbon are coaxially mounted . these two elements are included together in a pressure container . according to the above described construction , in the compressor at a high pressure exceeding 40 mpa , quality of the discharge gas can be kept and the compressor can be made compact .