To make sure safety for the following car only through viewing a rear view mirror when the car is going to change the lane or intrude to a highway, by eliminating the right rear dead angle as the defect of a conventional rear view mirror.

A convex mirror 2 for use in a rear view mirror has a vertical curvature 3 and transverse curvature 4, and the latter 4 is solely enlarged. In this rear view mirror 1, the crosswise width of the following car is seen some narrowed, which gives however an effect of wide angle, and the right rear dead angle as the defect according to he conventional mirror arrangement is eliminated. Because the vertical curvature remains the same as conventional, the height of the car is seen the same as conventional, and one can check whether there is any car following in the same sense as conventional.