The substrate processing unit 1 comprises the rotating table 31 configured to hold substrate W, the processing chamber 37 which accommodates the rotating table 31, a lamp 61 is provided above the processing chamber 37 and configured to heat the surface of substrate W, the lamp chamber 60 which accommodates that lamp 61, a transmission window 62 disposed below the lamp chamber 60, and a plurality of nozzle 64 which supply cooling fluid G to the transmission window 62. Then the substrate processing unit 1 can suppress generating of a water mark or pattern collapse, and can perform good substrate processing.