A multistage centrifugal compressor includes a rotary shaft, and multistage impellers attached to the rotary shaft. Each of the impellers includes a hub, a shroud and blades therebetween in a radial cascade arrangement. An annular suction passage for guiding the fluid flow from the inward radial direction to a blade inlet is disposed upstream of the centrifugal impeller. A diffuser is disposed downstream of the centrifugal impeller. A bend portion is disposed downstream of the diffuser, and a return channel with a guide blade portion is disposed downstream of the bend portion. The annular suction passage at a hub side includes an axial parallel portion.