Air intake device

Provided is an air intake device configured so that, in an engine room, an air cleaner and a fresh air duct can be easily installed and sufficient maintenance space can be maintained. The air intake device is provided with the following: an air cleaner having a cylindrical case with bottom, which has an open end and in which is formed a flow inlet, a cover in which a flow outlet is formed and which closes the open end of the case, and a filter member that is interposed between the case and the cover and that partitions the internal space between the case and the cover into a dust side on the flow inlet side and a clean side on the flow outlet side; and a fresh air duct through which fresh air is introduced into the air cleaner. The air cleaner and the fresh air duct are mutually connected by a joining duct. The joining duct is provided with a wall part that, along with the case, constitutes the dust side. The wall part is attached along a direction that is vertical with respect to the flow inlet.