The invention discloses a self-adaptive adjusting device for backlash for end face oscillating tooth harmonic transmission, and relates to the self-adaptive adjusting device for the backlash. The self-adaptive adjusting device comprises a shell, an end face gear, a hollow screw, a limiting bearing I, a locking device, a limiting bearing II and a torsion spring; the end face gear is nested in the left side of the shell in an axial sliding mode; the hollow screw is connected to the end face gear in a threaded mode; the locking device is arranged at the right end of the hollow screw; the limiting bearing I is arranged on the right side of the hollow screw, and the two end faces of the limiting bearing I are attached to a locking disc and the shell respectively; a bearing block is arranged on the right side of the locking disc; the limiting bearing II is arranged on the bearing block, and the two end surfaces of the limiting bearing II are attached to the locking disc and the shell respectively; and the torsion spring is arranged between the locking disc and the shell. The self-adaptive adjusting device has the advantages that the backlash can be adjusted in a self-adaptive mode, the bearing capacity is high, the transmission precision is high, the transmission efficiency is high, and the overload protection function can be achieved.