PROBLEM TO BE SOLVED: To provide an endoscope apparatus which permits an endoscope bending in the bendable portion to be easily inserted into Vaters papilla.SOLUTION: The endoscope apparatus 1 includes a first over tube 10 having the endoscope E having the bendable portion Ea at the tip and a side opening 13 opened in the side wall of the tip and interpolating the endoscope E and a second over tube 20 having an opening 22 at the tip and interpolating the first over tube 10. The first over tube 10 can be projected from the opening 22 of the second over tube 20 and has an expandable first balloon 14 on the outside periphery nearer to the tip side than the side opening 13. The second over tube 20 has an expandable second balloon 24 on the outside periphery of the tip. The endoscope E can be projected from the side opening 13 by bending the bendable portion Ea with the side opening 13 of the first over tube 10 exposed from the opening 22 of the second over tube 20.
