A light source includes an arc tube having a light emission portion for emitting light. A reflector reflects the light toward an illumination receiving area with the arc tube fixed to the reflector. A housing houses the reflector to form a space through which cooling air flows. The housing has three delivery ports disposed side by side as ports from each of which the cooling air is delivered toward the direction of the light emission portion. A first delivery port included in the three delivery ports is located such that the center of the first delivery port is disposed substantially at a position aligned and runs parallel to the optical axis of the arc tube. Second and third delivery ports included in the three delivery ports are disposed in the vicinity of one and the other sides of a first delivery port, respectively, with respect to the optical axis.