A construction machine comprising: a machine room that houses an engine; a cooler disposed inside the machine room to cool the engine; an air passage forming member forming an air passage extending from an intake port to the machine room and including a curved section having a curved shape in the middle of the air passage; a cooling fan capable of generating both a normal wind that flows from the intake port toward the cooler through the air passage and a reverse wind that flows from the cooler toward the intake port through the air passage, the cooling fan being located downstream of the cooler with respect to a normal wind direction in which the normal wind flows; a dust-proof filter provided between the air passage and the cooler to capture foreign matter contained in the normal wind; a dust collection pocket provided at a position shifted from an inner wall surface of an outer corner part of the curved section to a downstream side in the normal wind direction along the normal wind direction, the dust collection pocket including an opening that opens to an upstream side in the normal wind direction and a bottom closing at a downstream side in the normal wind direction and configured to take in the foreign matter that has been separated from the normal wind by an inertia of the foreign matter in the curved section through the opening to collect the foreign matter; and a turning member including a lid section capable of closing the opening, the turning member provided in the air passage forming member so as to be turnable about a turning axis intersecting the normal wind direction to be thereby moved between a close position and an open position, wherein: the lid section opens the opening in the open position and closes the opening in the close position; and the turning member is configured to be turned to the open position by the normal wind and to be turned to the close position by the reverse wind. a machine room that houses an engine; a cooler disposed inside the machine room to cool the engine; an air passage forming member forming an air passage extending from an intake port to the machine room and including a curved section having a curved shape in the middle of the air passage; a cooling fan capable of generating both a normal wind that flows from the intake port toward the cooler through the air passage and a reverse wind that flows from the cooler toward the intake port through the air passage, the cooling fan being located downstream of the cooler with respect to a normal wind direction in which the normal wind flows; a dust-proof filter provided between the air passage and the cooler to capture foreign matter contained in the normal wind; a dust collection pocket provided at a position shifted from an inner wall surface of an outer corner part of the curved section to a downstream side in the normal wind direction along the normal wind direction, the dust collection pocket including an opening that opens to an upstream side in the normal wind direction and a bottom closing at a downstream side in the normal wind direction and configured to take in the foreign matter that has been separated from the normal wind by an inertia of the foreign matter in the curved section through the opening to collect the foreign matter; and a turning member including a lid section capable of closing the opening, the turning member provided in the air passage forming member so as to be turnable about a turning axis intersecting the normal wind direction to be thereby moved between a close position and an open position, wherein: the lid section opens the opening in the open position and closes the opening in the close position; and the turning member is configured to be turned to the open position by the normal wind and to be turned to the close position by the reverse wind. the lid section opens the opening in the open position and closes the opening in the close position; and the turning member is configured to be turned to the open position by the normal wind and to be turned to the close position by the reverse wind.