The insertion apparatus includes: a linearly-extending insertion section main body, an outer tube covering the outer circumference of the insertion section main body, and an annular band member provided on the outer tube in such a manner as to meander on an imaginary circle on the outer tube whose center is the same as the central axis of the insertion section main body. The annular band member is configured to shrink in the direction along the imaginary circle and thereby secure the outer tube to the insertion section main body.