To provide an anti-aircraft weapon system for preventing degradation in gun aiming accuracy by separately changing a calculating cycle after a firing calculation part to reduce an error occurring with an anticipated angle filer for a short-range rapid target.

There are provided a target tracking part which tracks a single target, a first extrapolating part which extrapolates a target specification acquired at the target tracking part, a firing calculation part which calculates firing based on the target specification which is extrapolated at the first extrapolating part, an anticipated angle filtering part which smoothes a gun drive position command given from the firing calculation part, and a second extrapolating part which extrapolates the gun drive position command smoothed by the anticipated angle filtering part. By inserting the first extrapolating part, a calculation cycle after the firing calculation part is shorter than that at the target tracking part.