A lens tube includes a standard member, a lens, a guide, and a pushing member. The standard member has a standard surface via which the standard member is to be mounted to a camera main body. The lens retainer retains at least one lens and is connected to the standard member movably along an optical axis of the at least one lens. The guide is provided facing the lens retainer in a radial direction of the at least one lens to guide the lens retainer along the optical axis. The pushing member pushes the lens retainer and the guide in opposite directions.