A construction machine comprising: a lower travelling body; an upper slewing body mounted on the lower travelling body so as to be able to slew and having a device accommodation space; devices accommodated in the device accommodation space and including an engine, a cooling fan, and a heat exchanger, the cooling fan adapted to rotate to introduce outside cooling air into the device accommodation space and blow the air through the heat exchanger; a guard cover to cover the device accommodation space, the guard cover including a first panel with an opening edge defining an opening for maintenance and a second panel positioned above the first panel and being pivotable so as to open and close the opening, the second panel having a peripheral portion adapted to be supported by the opening edge of the first panel in a state where the second panel closes the opening; and a seal member attached to the opening edge of the first panel and adapted to make close contact with the peripheral portion of the second panel in a state where the second panel closes the opening, characterized in that a part of the peripheral portion of the second panel and a corresponding part of the opening edge of the first panel are shifted from each other in an inward-outward direction to form an air suction port, which brings the device accommodation space into communication with an outside of the device accommodation space, between the second panel and the first panel, and wherein the corresponding part of the opening edge is inwardly recessed beyond the peripheral portion of the second panel so as to be located at an inwardly retracted position relative to the other portion of the opening edge to form the air suction port, the corresponding part forming an upright portion that stands upward, and the other portion of the opening edge supports the peripheral portion of the second panel at a lower side thereof in a state where the second panel is closed and the seal member makes close contact with a lower surface of the peripheral portion. a lower travelling body; an upper slewing body mounted on the lower travelling body so as to be able to slew and having a device accommodation space; devices accommodated in the device accommodation space and including an engine, a cooling fan, and a heat exchanger, the cooling fan adapted to rotate to introduce outside cooling air into the device accommodation space and blow the air through the heat exchanger; a guard cover to cover the device accommodation space, the guard cover including a first panel with an opening edge defining an opening for maintenance and a second panel positioned above the first panel and being pivotable so as to open and close the opening, the second panel having a peripheral portion adapted to be supported by the opening edge of the first panel in a state where the second panel closes the opening; and a seal member attached to the opening edge of the first panel and adapted to make close contact with the peripheral portion of the second panel in a state where the second panel closes the opening, characterized in that a part of the peripheral portion of the second panel and a corresponding part of the opening edge of the first panel are shifted from each other in an inward-outward direction to form an air suction port, which brings the device accommodation space into communication with an outside of the device accommodation space, between the second panel and the first panel, and wherein the corresponding part of the opening edge is inwardly recessed beyond the peripheral portion of the second panel so as to be located at an inwardly retracted position relative to the other portion of the opening edge to form the air suction port, the corresponding part forming an upright portion that stands upward, and the other portion of the opening edge supports the peripheral portion of the second panel at a lower side thereof in a state where the second panel is closed and the seal member makes close contact with a lower surface of the peripheral portion.