The present invention relates to a device and a method for calculating the number of shooting which accurately calculate the number of shooting by controlling a trigger of a gun and using a sensor measuring vertical retroaction of the gun in shooting start and finish times. The method for calculating the number of shooting includes a step of calculating a first shooting number from a solenoid control signal of a gun obtained between the shooting start time and the shooting finish time; a step of calculating a second shooting number from a vertical retroaction signal of the gun detected between the shooting start and finish times; and a step of calculating a final shooting number of the gun by using the first shooting number and the second shooting number. [Reference numerals] (AA) Start; (BB) End; (S610) Calculating a first shooting number from a solenoid control signal of a gun obtained between the shooting start time and the shooting finish time; (S620) Calculating a second shooting number from a vertical retroaction signal of the gun detected between the shooting start and finish times; (S630) Comparing the first shooting number and the second shooting number; (S640) First shooting number≠Second shooting number?; (S650) Determining the first shooting number or the second shooting number as a final shooting number; (S660) Determining the smaller shooting number among the first shooting number and the second shooting number as the final shooting number
