A center pillar structure of a vehicle includes: a center pillar that is disposed at a center portion in a length direction of a vehicle body and supports the vehicle body; a center pillar outer reinforcement panel that supports the center pillar as a basic frame of the center pillar; a side sill that extends in the length direction of the vehicle at a lower side of the center pillar; and a center pillar inner panel coupled to parts of the side sill and the center pillar outer reinforcement panel by being overlapped therewith to form the center pillar, and disposed farther inside in a width direction of the vehicle body than the center pillar output reinforcement panel. The side sill and the center pillar output reinforcement panel are integrated.