A substrate processing apparatus includes a holder and a heating device. The holder is configured to hold a central portion of a bottom surface of a substrate to be rotated. The heating device is configured to supply a heated fluid to the bottom surface of the substrate. The heating device includes multiple fins, a heat source, a fluid introduction unit and a fluid discharge unit. The multiple fins are arranged along a circumferential direction of the substrate to be located under the substrate at an outer side than the holder. The heat source is configured to heat the multiple fins. The fluid introduction unit is configured to introduce the fluid to the multiple fins. The fluid discharge unit is configured to discharge the fluid, which is heated while passing through the multiple fins, to the bottom surface of the substrate.