A valve device include a drive device cover that is placed outside a housing. The drive device cover receives a drive device of a valve and a rotational angle sensor. The drive device cover has a cover main body and a connector. The connector electrically connects the drive device and the rotational angle sensor to at least one external device. The connector is placed on one side of the cover main body where a pipe member is placed relative to the housing in a perpendicular direction that is perpendicular to an axial direction, and the connector projects from the cover main body on the one side of the cover main body.