Abstract: There are disclosed an apparatus and a method for chemical vapor deposition for a semiconductor film and the like, wherein a feed gas is supplied in a horizontal tubular reactor in the direction parallel to a substrate; a forcing gas is supplied therein in the direction perpendicular to the substrate; and the flow rate per unit area of the forcing gas which is supplied from a forcing gas introduction portion into the reactor is made lower in the central portion of the forcing gas introduction portion than in the peripheral portion thereof, or lower in the middle of a feed gas passageway than at both the end portions of the passageway.