To effectively dissipate generated heat in a casing for accommodating electronic equipment and cables relating to a digital communication field while reducing works such as maintenance or the like.

An accommodation box for accommodating the line collecting apparatus of an optical fiber line comprises a casing 31 for accommodating the line collecting apparatus, a pair of fans 32, 33 disposed on opposite surfaces of the casing 31, and a control unit 34 for controlling the drive of these fans 32, 33. The control unit 34 reverses a ventilation direction in the casing 31 by the fans 32, 33 periodically or in response to temperature rise in the casing 31.