A centrifugal compressor includes an impeller which includes a front surface, a back surface, and a side surface; a first wall portion which includes a first wall surface facing the front surface and forming a flow passage; a second wall portion which includes a second wall surface facing the back surface and the first wall surface; and a protruding wall portion which is provided at an outside in a radial direction in relation to the side surface of the impeller. The protruding wall portion includes a third wall surface extending from the second wall surface in the axial direction and facing the side surface of the impeller. The third wall surface further extends toward the first wall surface in the axial direction from a connection portion between the front surface and the side surface. The third wall surface and the side surface form a second gap therebetween.