The invention relates to a large light bar conveying device which comprises a cart, a clamping mechanism, a supporting mechanism and a driving mechanism, wherein the driving mechanism comprises a guide rod, a screw rod, a clamp, a nut, a crank, a driving bevel pinion, a driven bevel pinion, a driving shaft and a bearing seat; the guide rod and the screw rod are vertically connected to a bottom plate of the cart, a guide slot is arranged on the clamp, the nut is fixed on the clamp, and the clamp is connected with the screw rod through the nut; one end of the driving shaft is connected with the crank, the other end of the driving shaft is connected with the driving bevel pinion, and the driven bevel pinion is connected to the corresponding position at the lower part of the screw rod and meshed with the driving bevel pinion; the clamping mechanism is connected to the clamp, the screw rod can be rotated, and the clamp drives the clamping mechanism to move up and down; the supporting mechanism comprises a spring seat and a support frame, wherein the spring seat is fixed on the bottom plate of the cart, and the support frame is arranged on the spring seat. The invention has the advantages that the large light bar conveying device can be suitable for conveying different specifications of light bars, the clamping or clamp-removing action is very rapid, the on-machine suspension is stable and convenient, and the conveying security and the conveying efficiency are improved.