A joining apparatus includes an ultrasonic vibrating device, and an anvil roller facing the ultrasonic vibrating device with superimposed continua of front waistline portions and back waistline portions interposed therebetween. The anvil roller includes a protrusion configured to press the continua in a predetermined region between the anvil roller and the ultrasonic vibrating device, a motor configured to rotate the anvil roller, a belt configured to connect the anvil roller and the motor and to be driven by the motor, and a pressing mechanism configured to press the belt in a cross direction perpendicular to a driving direction of the belt.