A vehicle pillar structure includes a vehicle pillar and a transparent window member. The vehicle pillar includes a first pillar extending along an outer end of a windshield glass in a width direction of a vehicle, and a second pillar disposed away from the first pillar by a predetermined distance in a substantial front-and-rear direction of the vehicle. An outside of the vehicle is viewable through the transparent window member. The transparent window member is interposed between the first pillar and the second pillar, and covers an opening defined by the first pillar and the second pillar. The vehicle pillar has a curved shape defined by a straight portion extending in a substantial vertical direction of the vehicle in side view, and a curved portion curved from an upper end of the straight portion and extending in the front-and-rear direction of the vehicle.