A projector comprising: a light source device having a light source lamp and a housing for accommodating the light source lamp inside; a duct through which air discharged from the housing circulates; and a fan which discharges the air circulating through the duct, to outside the duct; wherein the housing has an exhaust port for discharging the air in the housing, the duct includes: an inlet which faces the exhaust port and introduces the air discharged from the exhaust port into the duct; a branching part which branches the air introduced from the inlet; a first duct part which extends along a first direction that is a direction orthogonal to an opening plane connecting an edge of the exhaust port and also heading toward the inlet from the exhaust port, and through which the air introduced from the inlet can circulate via the branching part; and a second duct part which extends from the branching part, along a second direction intersecting with the first direction, and through which the air introduced from the inlet can circulate via the branching part, the fan is arranged at a position for sucking the air circulating through the second duct part, the first duct part includes: a plurality of sidewall parts forming the first duct part; an opening which is formed at least in one of the plurality of sidewall parts and through which the air circulating through the first duct part is discharged out of the first duct part; and a mesh covering the opening. a light source device having a light source lamp and a housing for accommodating the light source lamp inside; a duct through which air discharged from the housing circulates; and a fan which discharges the air circulating through the duct, to outside the duct; wherein the housing has an exhaust port for discharging the air in the housing, the duct includes: an inlet which faces the exhaust port and introduces the air discharged from the exhaust port into the duct; a branching part which branches the air introduced from the inlet; a first duct part which extends along a first direction that is a direction orthogonal to an opening plane connecting an edge of the exhaust port and also heading toward the inlet from the exhaust port, and through which the air introduced from the inlet can circulate via the branching part; and a second duct part which extends from the branching part, along a second direction intersecting with the first direction, and through which the air introduced from the inlet can circulate via the branching part, an inlet which faces the exhaust port and introduces the air discharged from the exhaust port into the duct; a branching part which branches the air introduced from the inlet; a first duct part which extends along a first direction that is a direction orthogonal to an opening plane connecting an edge of the exhaust port and also heading toward the inlet from the exhaust port, and through which the air introduced from the inlet can circulate via the branching part; and a second duct part which extends from the branching part, along a second direction intersecting with the first direction, and through which the air introduced from the inlet can circulate via the branching part, the fan is arranged at a position for sucking the air circulating through the second duct part, the first duct part includes: a plurality of sidewall parts forming the first duct part; an opening which is formed at least in one of the plurality of sidewall parts and through which the air circulating through the first duct part is discharged out of the first duct part; and a mesh covering the opening. a plurality of sidewall parts forming the first duct part; an opening which is formed at least in one of the plurality of sidewall parts and through which the air circulating through the first duct part is discharged out of the first duct part; and a mesh covering the opening.