A seat belt buckle for receiving a tongue connected to a seat belt webbing. The buckle includes a first ejector spring in a position out of an area α of the path of movement of an engagement portion of the tongue and an imaginary extended area β extended from the area α in the direction of movement of the engagement portion, and on the outer side of a base. A second ejector spring is provided in a position out of at least one of the area α and the imaginary extended area β, and on the outer side of the base 8. A bracket for fixing the buckle to the vehicle body can be provided closer to a tongue insertion hole, thereby reducing the length of the buckle in the tongue insertion direction.