A compressor casing includes a casing insert with a flexible element in the force flux between the insert wall contour and the outer compressor casing. The flexible element is assembled from a support ring and ribs, wherein the ribs axially in front of the support ring and the ribs axially behind the support ring are arranged in an offset manner in relation to each other. Due to the arrangement of the ribs in an offset manner, the axial force flux between the insert wall contour and the outer compressor casing is deflected twice, and an axially compliant flexible construction is achieved.