The invention particularly relates to a bender of a power transmission circuit externally exposed down lead. The bender of the power transmission circuit externally exposed down lead resolves the problem that when an existing down lead is bent, time and labor are wasted, and the bending effect is poor. The bender comprises two supporting frames distributed in a front and back mode, wherein a supporting plate is fixed between the two supporting frames, a connecting block is arranged under the supporting plate, a round rod penetrates through the connecting block, a pedal is arranged on the round rod on the left side of the supporting plate in a sleeved mode, a pressing plate is arranged on the upper surface of the supporting plate, locking bolts are screwed on the front side and the rear side of the pressing plate, an ejection pressing bolt is screwed on the pressing plate, a bending block is arranged at the front end of the supporting plate, a bending hole is formed in the right end of the bending block, rotary plates are fixed at the front end and the rear end of the bending block, a pin shaft penetrates between each rotary plate and the adjacent supporting frame, a limiting hole is formed in the lateral wall of each pin shaft, a limiting bolt matched with the corresponding hole is screwed on each rotary plate, and an ejection pushing bolt is screwed on each supporting frame. The bender of the power transmission circuit externally exposed down lead effectively improves bending efficiency and guarantees the bending curvature.