To provide compressor structure of a turbocharger, eliminating the need for replacement of a bearing housing, even when replacing a compressor impeller for changing the capacity of an engine.

In the compressor structure of a turbocharger having the compressor impeller 8 and a diffuser 15, the diffuser 15 is detachably attached on a bearing housing 3 side. When the compressor impeller 8 is replaced to change a diameter D1 of the compressor impeller 8 according to change in the capacity of the engine, a mounting position of the diffuser 15 with respect to the housing 3 side is at the same position before and after the replacement of the compressor impeller 8. When the compressor impeller 8 is replaced with one having a different diameter D1, the compressor structure can accommodate it without replacement of the bearing housing 3.