A swash-plate type compressor wherein a plurality of pistons fitted into a plurality of cylinder bores having their center on a circle are reciprocated by a swash-plate secured to a rotary shaft at a tilt angle. A swash-plate chamber rotatably accommodating the swash-plate concurrently functions as a passage for the refrigerant gas sucked, and an annular refrigerant gas passage, whose external diameter is larger than that of a circumcircle of the aforementioned cylinder bores and whose inner side is open to the swash-plate chamber, is formed on the external side of the swash-plate chamber. This annular passage for the refrigerant gas sucked functions as a by-pass therefor, diminishes the flow resistance of the refrigerant gas, and facilitates the cooling of the pistons with a result of reducing the operation noise produced from the engaging portion of the pistons and the swash-plate.