A quick-release fastener for a vehicle seat belt (21) with a fitting part (1), and a fastening part (7). The fitting part (1) has a first opening (2), and a second opening (3), in which the fastening part (7) can be locked to a locking head (6). The fastening part (7) can be inserted into the opening (3) in which a spring element (14) is arranged in an assembly position (I), and the spring element (14) can be moved into the locked position (II). A housing (100) is adapted to the shape of the fitting part (1) with the locking head (6) retained therein. The mounting (112) is shaped n such that the fitting part (I) with the locking head (6) can be completely received in the mounting (112) only when the locking head (6) is in the locked position (II).