The invention belongs to the technical field of anchor cable supporting equipment, and particularly relates to a coal mine underground fully-automatic anchor cable drilling rig. The problems that an existing anchor cable supporting mode is low in automation degree, low in supporting efficiency, large in labor intensity of workers, poor in working environment, poor in safety and the like are solved. The coal mine underground fully-automatic anchor cable drilling rig comprises a rack, a feeding mechanism, a drilling rod bin, a drilling box and an anchor cable mounting device; the feeding mechanism, the drilling rod bin and the anchor cable mounting device are mounted on the rack; the feeding mechanism provides feeding power for lifting of the drilling box and is fastened in the middle of therack through bonding bolts; the drilling rod bin provides a temporary storage space for drilling rods and is mounted on the side face of the rack; and the anchor cable mounting device serves as a device for spraying cartridges, conveying anchor cables and dismantling and shearing the anchor cables, and is overall placed on the rear portion of the rack. Full automation of the supporting processesof storing the drilling rods, connecting the drilling rods, dismantling the drilling rods, spraying the cartridges, mounting the anchor cables, fastening the anchor cables and the like can be achieved, and thus the automation degree of anchorage construction equipment is increased.