A vehicle front-view monitoring system takes fail-safe measures when a fail-safe measure-interruption requirement using first parameter are met on a monitored image for a predetermined first period. The functions interrupted by the fail-safe measure is resumed when a fail-safe measure-release requirement using second parameter which is different from the first parameter is met within a predetermined second period after the fail-safe measure-interruption requirement has been met. The first period is variable in accordance with how accurately lane marking on a road in the monitored image is recognized.