Abstract: A rolling piston compressor comprising: a casing of circular cross-section; a rolling piston supported within the casing on a drivable eccentric shaft so as to be freely rotatable thereon and adapted to roll on the internal surface of the casing in the course of rotation of the shaft; at least one separating slide slidably supported in the casing and resiliently urged by the action of a spring against the circumference of the rolling piston, said slide being disposed between an inlet port for drawing in a medium which is to be compressed and an outlet port for the delivery of the compressed medium, and being associated with a device for locking the separating slide in a position in which the free edge does not bear on the rolling piston circumference.