The volume changeable device of a circling vane compressor comprises the compressing section, driving section, round vanes with circling vanes of the compressing section, compressing chamber formed by the ring space and outside of the cylinder interior and the said round vane having a linear slider in straight reciprocating movement along the cylinder's sliding guide face, and a pair of side through channel symmetrically set on both sides of the broken part with whose middle as the center on the sliding contact surface one side of the linear slider. Opposite to the linear slider, inside the said cylinder, a sliding valve is set to move forward, set back, contact or open the broken part driven by the driving part. With circling vanes circling in the cylinder with simple valve operation, it can realize compression model change both in the inside compressing chamber or the outside compressing chamber, and change the volume of the compressor, not only ensuring the using economy of the compressor, but also preventing the abrasion for relevant components and supply waste while turning on or off the compressor.