Conveyance device and image forming device

A conveyance device that conveys paper through a conveyance path along a surface thereof includes: a conveyance guide that has a guide surface to be a wall surface on one side of the conveyance path, an opening being formed in the guide surface; a paper detection unit at least including a detection member, which is arranged in a space that communicates with the conveyance path through the opening, and configured to detect, with the detection member, a leading end of the paper that reaches the opening; and a movable body that brings the detection member into a retracted state, in which a main part thereof is covered from the space, after the leading end of the paper is detected.