A driving force transmission mechanism (1) for transmitting a driving force from a driving source has the following arrangement. That is, the driving force transmission mechanism (1) includes a linear or rod-shaped flexible manipulation wire (95, 96), an inner pipe (2) serving as a flexible guide member in which the manipulation wire (95, 96) is inserted, an outer pipe (3) provided radially outside the inner pipe (2) and configured to suppress deformation of the inner pipe (2).
