A scroll-type variable-capacity compressor is disclosed in which a single spool is moved to open or close bypass ports and thereby change the capacity of compression chambers. Especially, the capacity can be controlled in satisfactory manner by opening the bypass ports to a specific position. Specifically, a first bypass port is arranged in the neighborhood of the contact point between the inner surface of the spiral wall of a fixed scroll and the outer surface of the spiral wall of a movable scroll making up one of the compression chambers with the capacity thereof reduced to a predetermined level. A second bypass port is arranged at a position on the side beyond a discharge port from the first bypass port but where the discharge port is not located on the line connecting the particular position and the first bypass port. The opening of the second bypass port is arranged at such a position as to be closed by the spiral wall of the movable scroll defining the other compression chamber in the state described above.