An endoscope includes a balloon injection channel a first opening portion configured to open in an operation portion a connecting tube 50 provided with a second opening portion 50k and a notch 50s, where the second opening portion 50k is communicated with the first opening portion a balloon pipe sleeve 52 a branch channel connection unit 56 configured to hold a first end portion of the balloon pipe sleeve 52 and provided with a rotation restriction portion 55d which is a protrusion fitted in the notch 50s and a fixing member 63 configured to fix the branch channel connection unit 56 to the connecting tube 50.
