A velocity calculating device and a hood raising apparatus for a vehicle are provided. In order to calculating velocity of the vehicle, velocity pulse signals from a velocity sensor 5 are inputted to a CPU 33. Further, it is executed to calculate average velocity V2 at intervals of a standard period T2 and acceleration &agr; at intervals of a period Tb on the basis of the velocity pulse signals. Next, on the basis of the calculated average velocity V2 and the acceleration &agr;, momentary velocity V3 at intervals of the period Tb is calculated. It is carried out to measure a passing of time t3 from the input of velocity pulse signal till a time when the output of calculation results is required, while momentary velocity V4 at a point of time when the output of calculation results is required is estimated on the basis of the momentary velocity V3 and the acceleration &agr;.