The present invention provides a transmission mechanism and a surgical instrument. The transmission mechanism is provided in the surgical instrument to drive the end instrument (20) disposed at the end of the surgical instrument, and the first and second guide mechanisms (8, 9, 16, 17) are provided. And a third drive shaft (1, 2, 3) and first, second, third and fourth traction bodies (4, 5, 6, 7). Three drive shafts (1, 2, 3) are provided in parallel. The first and second traction bodies (4, 5) are wound around the first drive shaft (1) in opposite directions and partially fixedly connected to the first drive shaft, and are guided by a guide mechanism ( After changing the direction by 8, 9, 16, 17), it is fixedly connected to the end device (20). The third and fourth traction bodies (6, 7) are wound around the third drive shaft (3) in opposite directions and partially fixedly connected to the third drive shaft, and are guided by the guide mechanism ( After changing the direction by 8, 9, 16, 17), it is fixedly connected to the end device (20). The guide mechanism (8, 9, 16, 17) is disposed between the guide mechanism (8, 9, 16, 17) and the end device (20) when the second drive shaft (2) rotates. The direction of movement of the parts of the first and second traction bodies (4, 5) is the third and second positions arranged between the guide mechanism (8, 9, 16, 17) and the end device (20). It is comprised so that it may become opposite to the moving direction of the part of 4 tow bodies (6, 7). The surgical instrument has the transmission mechanism. [Selection] Figure 1本発明は伝達機構および手術器具を提供する。伝達機構は、手術器具の端部に配置された端部器具（２０）を駆動するために手術器具に設けられており、ガイド機構（８，９，１６，１７）と、第１、第２および第３の駆動軸（１，２，３）と、第１、第２、第３および第４の牽引体（４，５，６，７）とを有する。３つの駆動軸（１，２，３）が平行に設けられている。第１および第２の牽引体（４，５）は、反対方向に第１の駆動軸（１）に巻き付けられ且つ第１の駆動軸に部分的に固定して連結されており、ガイド機構（８，９，１６，１７）によって方向を変化させた後、端部器具（２０）に固定して連結されている。第３および第４の牽引体（６，７）は、反対方向で第３の駆動軸（３）に巻き付けられ且つ第３の駆動軸に部分的に固定して連結されており、ガイド機構（８，９，１６，１７）によって方向を変化させた後、端部器具（２０）に固定して連結されている。ガイド機構（８，
