Abstract: A seat belt buckle for cooperation with an insert tongue comprises a swivel latch mounted in a frame to be movable between a locked position and a released position, and a helical pressure spring which has a first end supported by said swivel latch and a second end supported by a locking member. The spring is held by a spring receptacle which is defined by two ridges on said frame and which surrounds a spigot on said locking member. The second pressure spring end and said spring receptacle are configured such that said second spring end is self-centered on said spigot. Due to this configuration, a malassembly of the spring is excluded.