PROBLEM TO BE SOLVED: To provide a tape rewinding prevention mechanism of a binding device, which can improve operability and improve cuttability of a binding tape, by securing a tape holding margin of a tape holding mechanism.SOLUTION: A second guide plate 22 is pushed by a rib 47, which is formed in an operation plate 23, in timing when a mating part of a binding tape 7 is contact-bonded. Thus, a clearance between a first guide plate and the second guide plate 22 is narrowed, and an adhesive surface of the binding tape 7 is stuck on the second guide plate 22. This enables an end 7A of the binding tape 7 to be reliably held by a tape holding plate of a tape holding mechanism, and enables an improvement in operability of a binding device 1.
