To provide a binding tape guide mechanism capable of preventing jam from occurring at a corner for changing the conveying direction when both edges in the width direction of a longitudinal binding tape are guided and conveyed, and to provide a large band binding machine using the mechanism.

The binding tape guide mechanism 100 guides both edges in the width direction of the longitudinal binding tape T and forms a conveying path for the binding tape T. A correcting part 232 which pushes an intermediate part in the width direction of the binding tape T conveyed toward the outside direction of the curve of the corner 215 is provided immediately upstream side of the corner 215 for changing the conveying direction.