PURPOSE: To obtain an air flow in proportion to valve opening area even at deceleration, in an air controller of an automobile, by providing a small hole to a cylindrical core in a reduction gear.

CONSTITUTION: A main passage, provided with a throttle valve 2, and a reduction passage 12, mounted with a reduction gear 7, are provided in an air valve main unit 1. Manifold internal pressure is controlled by a load of a valve 10 and spring 9 in the reduction gear. A small hole 13 is provided to a cylindrical core 15, and exfoliation of air is eliminated in the downstream of the core 15 to flow a quantity of much air. In this way, an air quantity, in proportion to valve opening area, can be obtained even at deceleration.