A driver monitoring apparatus includes: a biosensor signal acquiring portion configured to acquire a biosensor signal detected by a biosensor provided in a steering wheel, a biosensor signal storage portion configured to store first biological information acquired by the biosensor signal acquiring portion during the manual driving mode; a first determination processing portion configured to determine whether or not a driver who is to drive during the manual driving mode is gripping the steering wheel, based on second biological information acquired by the biosensor signal acquiring portion and the first biological information read out from the biosensor signal storage portion, if the autonomous driving mode is switched to the manual driving mode, and a first signal output portion configured to output a predetermined signal that is based on the result of the determination performed by the first determination processing portion.