An intraocular lens insertion device, comprising: a body having a lens placement section that holds a lens and a tube section that guides said lens, said lens defining an optical area, a front portion that faces the tube section and a back portion that is spaced from and diametrically opposed to the front portion, said lens placement section being provided with a deformation mechanism that includes an upper holding member that includes a rib having a contact surface with a curved section prevents the contact surface from contacting the optical area of the lens and spaced front and back edges that are sized and positioned relative to said lens such that they contact the front and back portions of said lens from above along the advancement axis both prior to and after a lens folding caused by the deformation mechanism, and a lower holding member that includes first and second placement surfaces, first and second inclined surfaces and an arcuate surface that unites the inclined surfaces, the first and second placement surfaces being sized and positioned relative to said lens such that they support spaced side portions of said lens on opposite sides of said lens advancement axis; and a lens discharge mechanism that is installed in an advancement axis; characterized by said lower holding member is movable relative to said upper holding member in such a manner that said deforming mechanism folds said lens into a U-shape while said contact surface prevents movement of said lens along said lens advancement axis and maintains the position of a part of said lens on the advancement axis before, during and after folding said lens where it can be discharged by the lens discharge mechanism. a body having a lens placement section that holds a lens and a tube section that guides said lens, said lens defining an optical area, a front portion that faces the tube section and a back portion that is spaced from and diametrically opposed to the front portion, said lens placement section being provided with a deformation mechanism that includes an upper holding member that includes a rib having a contact surface with a curved section prevents the contact surface from contacting the optical area of the lens and spaced front and back edges that are sized and positioned relative to said lens such that they contact the front and back portions of said lens from above along the advancement axis both prior to and after a lens folding caused by the deformation mechanism, and a lower holding member that includes first and second placement surfaces, first and second inclined surfaces and an arcuate surface that unites the inclined surfaces, the first and second placement surfaces being sized and positioned relative to said lens such that they support spaced side portions of said lens on opposite sides of said lens advancement axis; and an upper holding member that includes a rib having a contact surface with a curved section prevents the contact surface from contacting the optical area of the lens and spaced front and back edges that are sized and positioned relative to said lens such that they contact the front and back portions of said lens from above along the advancement axis both prior to and after a lens folding caused by the deformation mechanism, and a lower holding member that includes first and second placement surfaces, first and second inclined surfaces and an arcuate surface that unites the inclined surfaces, the first and second placement surfaces being sized and positioned relative to said lens such that they support spaced side portions of said lens on opposite sides of said lens advancement axis; and a lens discharge mechanism that is installed in an advancement axis;