There is disclosed an intake control valve device for an internal combustion engine in which a high sealing effect of a valve can be achieved even if dispersions in the machining precision etc. of the valve, a valve shaft and other portions as well as thermal strain deformation of these parts cause. The intake control valve device includes a butterfly-type valve provided in an intake passage in a body. A valve seat surface, which can face an outer peripheral portion of an upstream-side surface of the valve at one half-periphery portion of the valve, disposed on one side of a valve shaft, is formed on the body, and another valve seat surface, which can face an outer peripheral portion of a downstream-side surface of the valve at another half-periphery portion of the valve, disposed on another side of said valve shaft, is formed on the body. The angle .theta..sub.3 of inclination of each of the two valve seat surfaces is larger than the angle .theta..sub.4 of inclination of the valve in its fully-closed condition.