A safety belt buckle includes a buckle member, a hook, a stop member, and a latch member. The buckle member has a chamber therein, which is communicated with an opening. The latch member has a tongue plate which is inserted into the chamber through the opening. The stop member and the hook are provided in the chamber, and the latch member is not able to be detached from the buckle member because that the stop member stops the hook from moving to engage the tongue plate. By pressing a press button on the stop member, the stop member is moved to a predetermined position, and no longer stops the hook from disengaging the tongue plate. The latch member is able to be detached from the buckle member at this time.