To provide a radar device that detects an angle capable of avoiding a target that may collide with a single beam and controls to avoid the collision without requiring any additional equipment.

The vehicle type of a target is judged from a detected reflection area, then the width of the target is detected, and an angle required for avoiding collision is obtained from the detected width of the target and the distance to the target. The reflection area is obtained by performing the fast Fourier transform of the reflection waves of the radar and according to the maximum value of a curve being obtained and a length where a threshold curve at the vehicle distance at that time crosses the above curve. Further, it is judged whether the own vehicle may collide with a preceding vehicle that is the target according to the vehicle distance and the relative speed obtained from the radar, and required treatment is taken based on an angle required for avoiding the collision mentioned above.