A hearing aid contains an ear insert which has an earpiece and a connection part which is connected to a receiver. The earpiece and the connection part each has a plug connector and are connected together by the plug connectors. One plug connector is a connection piece which extends in an axial direction along a longitudinal axis and has a thickened portion in the radial direction, and the other plug connector engages behind the thickened portion in order to axially fix the earpiece to the connection part. The thickened portion has an undercut and forms a retaining surface which runs into the thickened portion in a wedged manner. In this manner, the earpiece is attached to the connection part in a particularly secured manner.