The present invention relates to a bonding device which can suppress positional displacement of an end portion of a lower sheet and an end portion of an upper sheet with respect to a nozzle, and which can stably convey the lower sheet and the upper sheet. The bonding device 1 includes a lower clamp roller 501, an upper clamp roller 601, a support member 315, a lower detection portion 535, and an upper detection portion 635. Each of the lower clamp roller 501 and the upper clamp roller 601 can rotate with an axial direction thereof being the front-rear direction. A lower specified end portion 8A, which is a right end portion of the lower sheet 8, is clamped between the lower clamp roller 501 and the support member 315. An upper specified end portion 6A, which is a left end portion of the upper sheet 6, is clamped between the upper clamp roller 601 and the support member 315. The lower detection portion 535 detects whether the lower specified end portion 8A is located at a lower detection position P, which is a predetermined position. The upper detection portion 635 detects whether the upper specified end portion 6A is located at an upper detection position Q, which is a predetermined position. The bonding device 1 switches a rotating direction of the lower clamp roller501 and the upper clamp roller 601 in accordance with detection results of the lower detection portion 535 and the upper detection portion 635.