Provided is a platform door device which makes it possible to reduce the length of time for a replacement operation when a panel-shaped portion of a door is damaged. The platform door device comprises a door, and a driving mechanism for moving the door forwardly and backwardly to close and open a gate on a platform. The driving mechanism includes a motor, a rotation body adapted to be rotated by the motor, and a driven body adapted to be driven according to the rotation of the rotation body so as to move the door, and the door has a panel-shaped main body, and a base segment detachably joined to the main body and attached to the driven body.