An insertion instrument includes an insertion portion, an operation portion connected to the insertion portion, a first bending region and a second bending region on a distal end side of the insertion portion, a bending wire that is inserted through the inside of the insertion portion and the operation portion and that causes the bending portion to perform a bending operation, a wire movement restriction portion that restricts the bending wire, a bending state switching mechanism that switches between a first bending state in which the first bending region and the second bending region perform a bending operation and a second bending state in which only the first bending region performs a bending operation, and a wire movement restriction portion switching mechanism that switches the wire movement restriction portion in synchrony with an operation that switches to the first bending state or the second bending state.
