A driver monitoring system (1) recognizes a state of a driver (S210) and determines a recognition stability (S215). When the recognition stability is less than a predetermined reference value, the driver monitoring system makes a request to the driver for a different action that is different from an action requested when the recognition stability is not less than the reference value (S230, S235, S240, S260, S310) and detects an action of the driver that responds to the request (S270, S315). This configuration can keep the wakefulness of the driver, even when the driver state such as wakefulness cannot be correctly recognized.
