To enable to sufficiently secure the capacity of a duct, by constituting an open-/clos-able wiring duct device equipped on a desk by equipping both right and left end parts each with attaching part to the lower face of the top plate at the upper end and both front and rear lid parts with a prescribed distance between the upper end and the lower face of the top plate and with each top end to be opened and closed.

This duct device 1 is constituted of right and left pieces 3, 5, and a bottom part with a lid part 19 and a bottom part, and right and left pieces 3, 5 form each outward facing attaching piece 8 at the upper end. On the both ends of the eight and left pieces 3, 5 in the longitudinal direction, opposite pieces 12, 12 facing the lid part 19 of the duct main body 6 are formed by making the upper ends thereof engaged parts 14 to be engaged with an engaging hook 24 of the duct main body 6. In a condition the engaging hook 24 engages with one of the engaged parts 14, the engaged part 14 of the opposite piece 12 is equipped on a position lower than the position of the attaching piece 8 at a prescribed distance so that a stored article with a small cross section diameter is stored in the duct through an opening part between the upper end of the lid part 19 and the lower face of the top plate.