A surgical instrument is disclosed. The surgical instrument, which has an effector for engaging the surgical site joined to one end and a driving part for operating the effector joined to the other end, includes: a first shaft, which has one end joined with the driving part, and which extends along a first lengthwise direction; and a second shaft, which extends along a second lengthwise direction that forms a particular angle with the first shaft, and which has one end joined with the other end of the first shaft such that the second shaft is rotatable about an axis following the second lengthwise direction. Thus, it is possible to conduct surgery using several of such surgical instruments without having the instruments obstruct one another, and the surgical instrument can be made to have different usage modes according to what length it is set to.