A safety belt buckle assembly includes a base, two combination pieces, and a locking member. The base has a mounting section, a belt passage section, a receiving slot, a connecting portion, and an insertion opening. The combination pieces are located at two sides of the receiving slot. Each of the combination pieces has a shaft receiving groove and an insertion hole. A shaft is mounted in the shaft receiving groove of each of the combination pieces and extends through a shaft hole of the locking member. Each of the combination pieces is provided with a resting member, an elastic member, and a covering member mounted in the insertion hole respectively. The locking member is pivotally mounted on the base and has a locking portion locked by the resting member of each of the combination pieces.

A buckle having an excellent design property is provided. [Solution] In a buckle for a belt in which a socket member and a plug member engage with each other, a buckle 10 is formed by forming the socket member including a front face portion 25 having an approximately flat surface; a back face portion 26 provided in such a way as to face a reverse face of the front face portion 25, and forming an engagement hole 21 with which the plug member engages between the back face portion 26 and the front face portion 25; a pressing piece 28 formed in the front face portion 25 by being divided by a slit 31 formed in the front face portion 25 and pressed for releasing an engagement with the plug member inserted into the engagement hole 21 to be engaged therewith; and a hinge portion 29 formed to be thinner than the pressing piece 28, connecting the pressing piece 28 to the same surface as the surface of the front face portion 25, and serving as a base point for a displacement when the pressing piece 28 is pressed.