A cylinder member includes: a cylinder body having a cross section and including a dent portion; a sheet member wrapped around the cylinder body and including a metal layer contacting the cylinder body and an outer layer; a first attachment member on a sheet member first end portion and removably attached to the dent portion; a second attachment member on a metal layer end portion protruding from the outer layer in the circumferential direction at a sheet member second end portion, the second attachment member being removably attached to the dent portion; a tension-applying mechanism pulling the second attachment member in a dent portion depth direction to apply tension to the metal layer; a projection on one of the second attachment member and metal layer end portion; and a fitting portion on other one of the second attachment member and the metal layer end portion and fitted to the projection.