In a radar apparatus, a laser light generating device generates a laser light. An optical device reflects the laser light to output it in a predetermined direction. The optical device has at least two reflective surfaces with different reflectance to the laser light. A reflected light detecting device detects a reflected light when the laser light is reflected by an object. An object detecting device detects the object based on the reflected light. An intensity changing device changes an intensity of the outputted laser light by switching the reflective surfaces. Thus, it can be prevented that an intensity of the reflected light becomes too large and an accuracy of detection of the object can be improved.