MONITORING DEVICE, STORAGE MEDIUM STORING COMPUTER PROGRAM FOR MONITORING, AND MONITORING METHOD

A monitoring device comprises a processor configured to estimate whether or not a non-stimulating environment has appeared in front of a driver which may cause the driver to have a lower alertness level or to engage in unfocused driving, based on multiple images taken of an environment ahead of a vehicle across a predetermined time period, and to act on the driver via a notification unit to increase a level of contribution to driving when the non-stimulating environment has appeared ahead.