Disclosed is a state detecting device that detects characteristic quantities regarding the driver that are represented by biological information such as the eyelid opening degree and frequency of heartbeat of the driver, identifies the group to which the state of the driver belongs between a Group 1 and a Group 2 into which multiple classes defined using the activity level of the driver as an indicator are sorted based on the detected characteristic quantities, outputs information including the identification results as output values, and detects the class to which the current state of the driver belongs based on loss values calculated from the output values. From the detected class, to what degree the activity level of the driver is impaired can be detected along with the level.