8. The driving maneuver assisting apparatus as claimed in claim 1 , wherein the driving maneuver assisting apparatus further comprises: a judging section configured to detect a current running environment around a vehicle and to judge whether or not the detected current running environment differs from a predetermined standard environment; and a second varying section configured to decrease the learning level calculated by the learning level calculating section when the judging section determines that the current running environment differs from the predetermined standard environment.
8. The driving maneuver assisting apparatus as claimed in claim 1 , wherein the driving maneuver assisting apparatus further comprises: a judging section configured to detect a current running environment around a vehicle and to judge whether or not the detected current running environment differs from a predetermined standard environment; and a second varying section configured to decrease the learning level calculated by the learning level calculating section when the judging section determines that the current running environment differs from the predetermined standard environment. 11. The driving maneuver assisting apparatus as claimed in claim 8 , wherein the judging section is configured to detect a current brightness around the vehicle, and to determine that the current running environment differs from the predetermined standard environment when the detected current brightness is lower than a predetermined standard state.