To provide an automatic tool changer capable of corresponding to multiple types of screws and ensuring a sufficient working space without using plural kinds of automatic screw fasteners.

This automatic tool changer is provided with a main driving bevel gear 11 which is engagable and disengagiable with a rotation transferring shaft 9 along with the reciprocating movement of the rotation transferring shaft 9 and is integrally rotatable when engaged with the rotation transferring shaft 9, a turret 17 which is rotatable in response to the rotation of the main driving bevel gear 11, the rotating tools 181, 18b, 18c which are sequentially arranged on the reciprocating movement path of the rotation transferring shaft 9 along with the rotation of the turret 17 and are connected to the rotation transferring shaft 9 on the predefined positions. The turret 17 is connected to a driven gear shaft 15 which is rotatable along with the rotation of the main driving bevel gear 11 and is arranged to have the predefined angle against the rotation center of the rotation transferring shaft 9.