The invention discloses an automatic drilling machine, which comprises a drilling machine body, at least one main shaft, a main shaft transmission device, a workpiece clamping device and a feeding device, wherein the axis of the main shaft is horizontally placed; the workpiece clamping device and the feeding device correspond to the main shaft; and the feeding device is fixedly connected with the main shaft transmission device or the workpiece clamping device. By adopting the technical scheme, the automatic drilling machine has the beneficial effects that: the main shaft of the automatic drilling machine is horizontally placed; a workpiece is extremely convenient for being placed in a workpiece clamp and taken out; the automatic drilling machine is easy to operate and low in manufacturing cost; the number and the size of machined holes are flexible in adjustment; a machining process does not depend on professional programming personnel.