An on-vehicle situation detection apparatus may include a detection unit to identify a driver and acquire driver status data and data about vehicle driving information or vehicle surrounding obstacles, a driving pattern learning unit to learn and store a driving pattern of a driver, based on the data acquired by the detection unit, a weighted value determination unit to determine a weighted value assigned to the information data acquired by the detection unit, based on the driving pattern learned by the driving pattern learning unit, a determination unit to determine a safe driving state of the driver, based on the data to which the weighted value determined by the weighted value determination unit is assigned, and a warning unit to warn the driver when the driver is determined to be not in the safe driving state.