This invention relates to a control system for the quantity of air to be inducted, which is suitable for use in controlling the idling speed of an engine, for example, for an automotive vehicle or the like. It is an object of the present invention to permit a change of the same degree to the quantity of air to be inducted for the compensation of a load without being affected by the temperature of the engine and also to precisely obtain inducted air in a quantity required inherently. The control system is constructed of STM valve (12) interposed in a bypass passage (11) of a throttle valve (8), ROM (36) for storing opening data for the setting of the position of the STM valve (12), the opening data corresponding to engine operation states, a limiter (13) interposed in the bypass passage (11) in series with the STM valve (12), the opening of the limiter being variable depending on the engine temperature, target opening setting device (45,46) for correcting a target opening on the basis of the engine temperature upon setting the target opening on the basis of the opening data obtained from the ROM (36) in accordance with an engine operation state, and an ISC driver (44) for controlling the opening of the STM valve (12) to the target opening from the target opening setting device (45,46).