To provide a movable platform fence device not requiring provision of any large number of obstacle sensing means and capable of reducing the cost.

Safety confirmation of inside a sensing region DA including a connecting passage PW leading from a doorway PF to a door opening D1 and the regions on both sides thereof is conducted by an obstacle sensing means 40, while another obstacle sensing means 40 installed at a door pocket fence 21 located beside the doorway PF is irradiated with a laser beam in such a way as crossing the connecting passage PW so that scanning is made in the direction along the passage PW or obliquely thereto, and thus obstacle sensing inside the sensing region DA can be executed effectively using one or a small number of sensing means 40.