Abstract: A belt transmission in which a transmission belt is reeved around each of a reversible drive pulley and a driven pulley and which includes a pair of tension pulleys provided respectively on the taut side and the slack side of the belt in contact therewith. The two tension pulleys are biased by an elastic body to tension the belt. A first link is connected to one of the tension pulleys, and a second link to the other tension pulley. The two links are each pivotally movable in a direction for the corresponding tension pulley to tension the belt and in a direction for the tension pulley to relieve the tension. The two links are pivotally movable about a common axis. When the direction of rotation of the drive pulley is changed, reversing the taut side and the slack side of the belt, the tension imparted to the belt by the tension pulleys is automatically adjusted properly by the pivotal movement of the two links.