To constantly control the belt tension of a belt conveyor as a numerical value.

A bearing box 11 of a tail pulley 2 of the belt conveyor I is slidably engaged with a guide rail 7 on a base frame 5. A screw rod 18 is passed through a tension receiving member fixed at the rear end side position of the guide rail in the longitudinal direction, and held by the tension receiving member at an arbitrary position. A load meter 20 is interposed between a tip part of the screw rod 18 and the bearing box 11. The measured value of the load meter 20 is displayed on a tension monitor panel 21, and the tension of the belt 3 is adjusted by displacing the screw rod 18 in the longitudinal direction based on the measured value.