Abstract: An integrated valve device for an intake manifold includes a casing having intake passages each connected to an intake port of an internal combustion engine and a through hole extending perpendicular to the intake passages. A valve shaft is received in the through hole. The valve shaft includes valve portions. Each valve portion is arranged to correspond to one of the intake passages. The valve portions are switchable between a first position, where each valve portion fully opens the corresponding intake passage, and a second position, where each valve portion partly blocks the corresponding intake passage. A recess may be formed in a wall defining each intake passage. In this case, when in the first position, each valve portion is entirely accommodated in the corresponding recess. When in the second position, each valve portion projects from the corresponding recess.