The invention provides a chain tension checking device. The chain tension checking device can be used for regulating the tension of a chain, the chain is effectively prevented from taking off, and the service life of the chain tension checking device is prolonged. The chain tension checking device comprises a rack and a chain wheel, wherein the chain wheel is in mesh transmission with the chain, and the chain is fixedly provided with a chain board. The chain tension checking device provided by the invention is characterized in that the rack is provided with a sliding rail, a wheel shaft of the chain wheel is arranged on a sliding block, the sliding block is arranged on the sliding rail, the sliding block is connected to a screw rod, the screw rod penetrates through the rack after being sleeved with a spring, the tail end of the screw rod is sleeved with an induction nut, and a sensor is arranged under the induction nut and is arranged on the rack.