A raindrop detection apparatus includes a light emitting unit for emitting light to an inner side of a windshield, a light receiving unit for receiving the light reflected by an outer surface of the windshield, a first lens unit which is arranged between the windshield and the light emitting unit to convert the light from the light emitting unit into parallel light, and a second lens unit which is arranged between the windshield and the light receiving unit to converge the reflected light at the light receiving unit. The second lens unit is larger than a radial cross section of the reflected light. An amount of raindrop landed on the outer surface of the windshield is detected based on an intensity of the light received by the light receiving unit.