A one-body type rain sensor is attached to a vehicle glass to differentiate a raindrop and an external object which fall down onto the vehicle glass, where the one-body type rain sensor includes a light emission unit which emits light which is inputted onto the vehicle glass, a second light emission module which emits light which is inputted onto the vehicle glass, a light receiving unit which receives the light which is emitted from the light emission unit and the second light emission unit and reflected off the vehicle glass, and a control unit which outputs the light that the light receiving unit has received, in the form of a signal, thereby operating a wiper of the vehicle.