To provide a vehicular circumference monitoring device without degrading distance measuring performance for small distance by reducing reflection by a mirror.

This vehicular circumference monitoring device for monitoring the vehicular circumference is provided with a transmitting antenna mounted inside a vehicular door mirror for radiating transmission waves through the mirror surface 7 of the door mirror, and a receiving antenna for receiving reflected waves from an object present in the vehicular circumference through the mirror surface 7 of the door mirror. A radio wave permeable surface for restraining the reflection on the mirror surface according to opening surfaces 8 of the transmitting antenna and the receiving antenna and for permeating the radio waves is formed on the mirror surface 7 of the door mirror. The radio wave permeable surface is formed by partially removing a reflection film 10 on the mirror surface 7, by cutting out part of the mirror surface or by forming metal slits on a part or the whole of the mirror surface.