To facilitate the design support of a head impact absorption structure for a vehicle.

An initial shape of a pillar is outputted as an initial condition for the design support of the head impact absorption structure for a vehicle (S10 to S14), and the position of the head gravity center of a passenger, an impact reference position (APR), impact target positions (APR2 and APR3) conforming to FMVSS201U are outputted using a tool which is formed into an template in advance (S16 to S22). Based on these, a dummy head (FMH) is arranged at an impact target position in an impact direction, and an energy absorption stroke at the pillar is acquired (S24 to S30). Then, a design parameter for the pillar is changed in order toward a target, automatic designing is performed, and the result is outputted (S32 and S34). A user can issue an instruction after checking the result (S36 and S38).