To provide a multi-stage centrifugal pump for use in an ultra-low temperature environment which precludes a drop in the force fastening a housing of each stage.

A frame 26 is installed surrounding a plurality of housings 20, and to the end of the frame 26, a holder 32 having a threaded hole is fixed. A fastening force for hosing at each stage is generated by driving a bolt 34 to be engaged in the threaded hole. The frame 26 is made of aluminum alloy, whereof the housings 20 are also made. The holder 32 and bolt 34 are made of stainless steel. At a low temperature, the frame 26 shrinks greater than the bolt 34, etc., and the bolt accordingly acts in such a way as to tighten, and a drop in the fastening force for the housing at each stage is precluded.