In order to provide a vehicle emergency brake system which can reliably actuate a second brake means, there are provided the second brake means 1 for braking the vehicle A by increasing the frictional resistance with the road surface, a millimeter wave radar 2 for detecting any obstacle in an advancing direction, a pedal speed sensor 5 for detecting the step-in speed of a brake pedal 4 for actuating a first brake means, and a controller 6 for actuating the second brake means 1. If hard braking by the first brake means is detected by the pedal speed sensor 5, whether or not the vehicle A is going to crash into an obstacle detected by the radar 2 is determined by the controller 6, and if determination is made that it will collide, the second brake means 1 is actuated. Thus, it is possible to reliably actuate the second brake means 1 in an emergency.