A side channel compressor with an impeller with delivery blades that has a seal to prevent leakage between the impeller and the impeller housing. A hub supporting the impeller connects it to a drive shaft. A housing surrounds the impeller, which rotates therein. A sealing device is provided between impeller and housing. The impeller is provided with a bearing ring that overhangs the hub. The overhanging portion of the bearing ring contacts a sealing ring held against a contact surface of the housing by a retaining ring. The retaining ring can be fastened to the housing by screws. The bearing ring can be provided with a corner recess to more securely engage the sealing ring.