A vehicular knob switch apparatus suitable for the attainment of size reduction and multi-function is provided. An operating knob is attached to a cylindrical housing rotatably from the exterior. Integral with the operating knob is a first gear which is disposed in the circumferential direction of the operating knob. A second gear is brought into mesh with the first gear in such a manner that the respective axes are orthogonal to each other. A support shaft of the second gear is held by a holder which is fixed to the interior of the housing. Also held by the holder is a printed circuit board which is disposed in the axial direction of the operating knob. Rotation of the operating knob is transmitted to a rotary volume through both gears and. The rotary volume is mounted on the printed circuit board, and first and second push switches, which are operated by key tops, respectively, are also mounted on the printed circuit board. The key tops are attached to the housing to allow to be operated from the exterior.