An object is to provide an endoscope conduit switching apparatus that can reliably switch a water feeding state and an air feeding state, and the endoscope conduit switching apparatus of the present invention is an endoscope conduit switching apparatus 13 configured to have a cylinder 31 (35) to which a plurality of conduits provided in an endoscope 1 are connected, and a piston 32 (45) that is fitted and inserted into the cylinder to be capable of advancing and retreating, and switch communication states of the plurality of conduits, and includes a seal member 53 configured to be provided at either one of the cylinder and the piston to isolate a gas flow conduit of the plurality of conduits from an outside, when the piston is in a normal state, and elastically contact a wall face of the other one, and a leak portion 35c configured to be provided on the wall face of the other one, and open the gas flow conduit to the outside after a liquid flow conduit of the plurality of conduits is closed, in a middle of an action of releasing a state where the piston is pushed in.
