ALERTING SYSTEM AND ALERTING METHOD

An alerting system includes: a notification unit, when a gaze dwell time of a driver exceeds a predetermined threshold, executing a notification at a predetermined conspicuousness level to the driver via an HMI device; a decision unit deciding on a notification parameter set including parameters defining a notification output timing and the conspicuousness level; a behavior recording unit recording presence/absence of a reactive behavior to the notification executed using the notification parameter set; and a reaction information recording unit recording reaction information where a reaction ratio, which is a ratio of the number of the notifications to which the reactive behavior occurs to the number of the notifications executed, is associated with each different notification parameter set, wherein the decision unit calculates and decides on, based on the reaction information, an optimal parameter set with which the reaction ratio is estimated to become the highest.