A construction machine, comprising: an engine; an engine room having an external wall enclosing an internal space for housing the engine; a cooled object disposed in the internal space of the engine room; and a cooling fan that is driven to produce cooling air flow for cooling the cooled object in the internal space of the engine room, wherein: the external wall of the engine room includes an upper wall portion located on an upper side of the internal space, the upper wall portion being formed with a first exhaust duct for guiding air inside the internal space to an outside of the engine room; characterized in that the first exhaust duct includes an upstream portion extending in a first horizontal direction and having one end which forms a first air inlet and a downstream portion extending upward from a terminal end of the upstream portion to a first air outlet opened upward in the upper wall portion, the first exhaust duct allowing air to flow from the first air inlet to the first air outlet; the upper wall portion is formed with a second exhaust duct for guiding air inside the internal space to an outside of the engine room; and the second exhaust duct includes a cross portion crossing the upstream portion of the first exhaust duct on an upper side of the upstream portion in a second horizontal direction perpendicular to the first horizontal direction, the second exhaust duct having a second air inlet opened downward at a position sideward of the upstream portion of the first exhaust duct with respect to the second horizontal direction and a second air outlet opened sideward at a position opposite to the air inlet across the cross portion in the upper wall portion, the cross portion allowing air to flow from the second air inlet to the second air outlet through an upper side of the upstream portion of the first exhaust duct. an engine; an engine room having an external wall enclosing an internal space for housing the engine; a cooled object disposed in the internal space of the engine room; and a cooling fan that is driven to produce cooling air flow for cooling the cooled object in the internal space of the engine room, wherein: the external wall of the engine room includes an upper wall portion located on an upper side of the internal space, the upper wall portion being formed with a first exhaust duct for guiding air inside the internal space to an outside of the engine room; characterized in that the first exhaust duct includes an upstream portion extending in a first horizontal direction and having one end which forms a first air inlet and a downstream portion extending upward from a terminal end of the upstream portion to a first air outlet opened upward in the upper wall portion, the first exhaust duct allowing air to flow from the first air inlet to the first air outlet; the upper wall portion is formed with a second exhaust duct for guiding air inside the internal space to an outside of the engine room; and the second exhaust duct includes a cross portion crossing the upstream portion of the first exhaust duct on an upper side of the upstream portion in a second horizontal direction perpendicular to the first horizontal direction, the second exhaust duct having a second air inlet opened downward at a position sideward of the upstream portion of the first exhaust duct with respect to the second horizontal direction and a second air outlet opened sideward at a position opposite to the air inlet across the cross portion in the upper wall portion, the cross portion allowing air to flow from the second air inlet to the second air outlet through an upper side of the upstream portion of the first exhaust duct. the external wall of the engine room includes an upper wall portion located on an upper side of the internal space, the upper wall portion being formed with a first exhaust duct for guiding air inside the internal space to an outside of the engine room; characterized in that the first exhaust duct includes an upstream portion extending in a first horizontal direction and having one end which forms a first air inlet and a downstream portion extending upward from a terminal end of the upstream portion to a first air outlet opened upward in the upper wall portion, the first exhaust duct allowing air to flow from the first air inlet to the first air outlet; the upper wall portion is formed with a second exhaust duct for guiding air inside the internal space to an outside of the engine room; and the second exhaust duct includes a cross portion crossing the upstream portion of the first exhaust duct on an upper side of the upstream portion in a second horizontal direction perpendicular to the first horizontal direction, the second exhaust duct having a second air inlet opened downward at a position sideward of the upstream portion of the first exhaust duct with respect to the second horizontal direction and a second air outlet opened sideward at a position opposite to the air inlet across the cross portion in the upper wall portion, the cross portion allowing air to flow from the second air inlet to the second air outlet through an upper side of the upstream portion of the first exhaust duct.