Onboard distance measuring device of underground heading machine

The utility model discloses an onboard distance measuring device of an underground heading machine, which comprises an onboard distance measuring transmitting device arranged above a heading machine body and a rectangular distance measuring receiving device suspended below a roadway top plate, and a first servo motor of the onboard distance measuring transmitting device is fixedly arranged in the middle of a bottom plate support; the rotating table is movably arranged on the bottom plate support, and the first servo motor drives the rotating table to rotate; the second servo motor is arranged on the outer side of the supporting plate located on the left side. The U-shaped swing arm is movably clamped between the two supporting plates with the opening facing downwards, and an L-shaped support is arranged at the upper end of the U-shaped swing arm. The ranging laser transmitter is arranged on the inner side of the L-shaped bracket; the third servo motor is arranged on the outer side of the L-shaped support, and