A construction machine comprising: an automotive vehicle body (2, 3); a working mechanism that is tiltably provided in an intermediate position in the left-right direction at a front side of said vehicle body (2, 3); a cab that is provided in a front portion of said vehicle body (2, 3) to be positioned in a left side of said working mechanism and is provided with an operator's seat for an operator to be seated on; and a right front housing cover that is provided in the front portion of said vehicle body (2, 3) to be positioned in a right side of said working mechanism for accommodating articles therein, said working mechanism comprising: a first boom whose base end is rotatably connected to said vehicle body (2, 3); a second boom that is rotatably connected to a tip end of said first boom; a boom cylinder (9, 10) of which one end (9C, 10C) in a length direction is connected to a cylinder mounting portion (15B2, 15C2) of said vehicle body (2, 3) in a position ahead of said base end of said first boom and the other end (9E, 10E) in the length direction is connected to a side of said tip end of said first boom to tilt said first boom to said vehicle body (2, 3); and a positioning cylinder that is provided between said first boom and said second boom to be positioned in a front surface side of said first boom for adjusting a folding angle of said second boom to said first boom, wherein said working mechanism is configured to take a traveling stance by a way that said boom cylinder (9, 10) is expanded to rotate said tip end of said first boom to the rear side and said positioning cylinder is compressed to rotate a tip end of said second boom to the lower side, characterized in that; in said traveling stance of said working mechanism, said boom cylinder (9, 10) is arranged to be inclined to the rear side at a tilting angle (α) in such a manner that said other end (9E, 10E) in the length direction is positioned in back of said one end (9C, 10C) in the length direction, a front surface plate of said right front housing cover positioned in the foremost portion, when a plane extending in the left-right direction along a front end (9A1, 10A1) of said boom cylinder (9, 10) in said traveling stance is formed as an inclined plate, inclined to the rear side by said tilting angle (α), and wherein said front surface plate is formed to be inclined to the rear side along said inclined plane of said boom cylinder (9, 10), and said front surface plate of said right front housing cover is arranged in a position of lining with said front end (9A1, 10A1) of said boom cylinder (9, 10) in the left-right direction along said inclined plane. an automotive vehicle body (2, 3); a working mechanism that is tiltably provided in an intermediate position in the left-right direction at a front side of said vehicle body (2, 3); a cab that is provided in a front portion of said vehicle body (2, 3) to be positioned in a left side of said working mechanism and is provided with an operator's seat for an operator to be seated on; and a right front housing cover that is provided in the front portion of said vehicle body (2, 3) to be positioned in a right side of said working mechanism for accommodating articles therein, a first boom whose base end is rotatably connected to said vehicle body (2, 3); a second boom that is rotatably connected to a tip end of said first boom; a boom cylinder (9, 10) of which one end (9C, 10C) in a length direction is connected to a cylinder mounting portion (15B2, 15C2) of said vehicle body (2, 3) in a position ahead of said base end of said first boom and the other end (9E, 10E) in the length direction is connected to a side of said tip end of said first boom to tilt said first boom to said vehicle body (2, 3); and a positioning cylinder that is provided between said first boom and said second boom to be positioned in a front surface side of said first boom for adjusting a folding angle of said second boom to said first boom, in said traveling stance of said working mechanism, said boom cylinder (9, 10) is arranged to be inclined to the rear side at a tilting angle (α) in such a manner that said other end (9E, 10E) in the length direction is positioned in back of said one end (9C, 10C) in the length direction, a front surface plate of said right front housing cover positioned in the foremost portion, when a plane extending in the left-right direction along a front end (9A1, 10A1) of said boom cylinder (9, 10) in said traveling stance is formed as an inclined plate, inclined to the rear side by said tilting angle (α), and wherein said front surface plate is formed to be inclined to the rear side along said inclined plane of said boom cylinder (9, 10), and said front surface plate of said right front housing cover is arranged in a position of lining with said front end (9A1, 10A1) of said boom cylinder (9, 10) in the left-right direction along said inclined plane.