A hearing instrument has housing with a plug-in connection. The plug-in connection connects hearing tubes, sound tubes or electrical signal lines. The hearing instrument ensures against an unintentional detachment of the tubes and lines from the housing. The housing has a locking apparatus. The plug-in connection is arranged in the housing. The locking apparatus is embodied to prevent an unintentional detachment of the plug in the plug-in connection. The locking apparatus includes a catch, with a latching plate, and being moveably mounted in the housing. The catch moves at right angles to the plug-in direction of the plug and the latch is pushed into the housing and is protected herein by a blocking facility against unintentionally being pushed out. The blocking facility includes a stop and a blocking element, against which the stop strikes when sliding out. With the moveable catch, an easy-to-operate locking process is achieved.