In order to be suitable for space-saving of a multi-functional processing machine in which a tool main spindle device is disposed at a center of an opposed biaxial lathe, there is provided an automatic tool exchanger provided in the multi-functional processing machine, the automatic tool exchanger including: a tool magazine that is disposed in a machine body front surface upper portion of the multi-functional processing machine and is configured to house multiple tools for exchange with respect to the tool main spindle device; a shift device configured to move the tool between the tool magazine and a tool exchanging position with respect to the tool main spindle device; and a tool changer configured to exchange the tool between the shift device and the tool main spindle device.