A radar apparatus is attached to a vehicle such that a direction at 90 degrees relative to a front-rear direction of the vehicle is included in a detection range, and transmits and receives radar waves. The radar apparatus detects an observation point relative speed that is a relative speed in relation to an observation point that has reflected the radar wave within the detection range and an observation point azimuth that is an azimuth at which the observation point is present. The radar apparatus determines that a moving object is detected when an expression expressed by V