To positively detect an actual target especially in a radar device for vehicle, by preventing beams from a light-emitting device from being diffused to the circumference away from a light transmission part.

An optical radar device is provided with a light-emitting device 1 for emitting light and a fixed mirror 4 with a mirror for reflecting and transmitting generated light and a support for supporting the mirror, and is fixed so that the reflection surface of the mirror for eliminating diffusion due to the distortion of the reflection surface of the mirror corresponds to the recess of the support. Also, to eliminate reflection in the light-emitting device 1, the inner surface of the light-emitting device 1 is pigmented to, for example, black or a color for absorbing light, woolen cloth is applied to it, or the like, thus reducing the reflection of light.