There is provided a co-rotating scroll compressor in which a driving-side scroll member including a spiral wall between facing end plates can be manufacturable at low cost. A driving-side scroll member (70) includes a first driving-side scroll portion (71), a second driving-side scroll portion (72), and a bolt (31). The first driving-side scroll portion (71) includes a first driving-side end plate (71a) and a first driving-side wall (71b), and is driven by a motor (5). The second driving-side scroll portion (72) includes a second driving-side end plate (72a) and a second driving-side wall (72b). The bolt (31) performs fixing while a front end in a rotation axis direction of the first driving-side wall (71b) and a front end in the rotation axis direction of the second driving-side wall (72b) face each other.

A scroll expander includes a driving scroll body having a first axis line a driven scroll body having a second axis line shifted with respect to the first axis line, a bearing plate including two plates coupled to the driven scroll body and having the second axis line a cylindrical driving pin attached to the driving scroll body, and a cylindrical guide ring attached to the bearing plate and having an inner diameter larger than an outer diameter of the driving pin. The driving pin includes an outer circumferential surface in contact with an inner circumferential surface of the guide ring. A hard film including diamond-like carbon is formed on the outer circumferential surface of the driving pin. The inner circumferential surface of the guide ring includes a polymer resin material with self-lubricity.