A front pillar structure for a vehicle includes a front pillar including a front pillar lower extending vertically and a front pillar upper extending obliquely from the front pillar lower. A connection member is coupled to a bottom end of the front pillar lower and connects a front side member and a side sill. The front pillar lower has an S-shaped cross section and the connection member has stepwise flanges coupled to the bottom end of the front pillar lower.