A construction machine comprising: a track structure ; a swing structure provided swingably at an upper portion of the track structure ; and an earth removing implement provided at at least either a front portion or a rear portion of the track structure , the earth removing implement including: a base portion frame mounted on the track structure ; a blade mounted on the base portion frame by using a linkage mechanism and a cylinder such that the blade can be raised and lowered; a fixed cover supported on the base portion frame and positioned above the linkage mechanism ; a movable cover that covers a gap between the fixed cover and the blade ; and a guide pin that guides the movable cover while the blade is being raised and lowered, wherein the movable cover includes a main surface portion having a lower end connected rotatably with the blade and an upper portion leaning on the fixed cover , the movable cover further including a side surface portion having a slot with which the guide pin engages, and wherein the slot is formed along positions of the side surface portion of the movable cover facing the guide pin when the movable cover rotates by having the upper portion of the main surface portion sliding over the fixed cover in accordance with a raising/lowering operation of the blade , characterized in that the guide pin is supported on the base portion frame , wherein the slot is configured such that the guide pin engages with the slot at a lower end position therein when the blade is raised to a highest position, and wherein the movable cover is configured such that a center of gravity thereof is positioned on a side closer to the base portion frame than to a pivotal point thereof when the guide pin engages with the slot . a track structure ; a swing structure provided swingably at an upper portion of the track structure ; and an earth removing implement provided at at least either a front portion or a rear portion of the track structure , the earth removing implement including: a base portion frame mounted on the track structure ; a blade mounted on the base portion frame by using a linkage mechanism and a cylinder such that the blade can be raised and lowered; a fixed cover supported on the base portion frame and positioned above the linkage mechanism ; a movable cover that covers a gap between the fixed cover and the blade ; and a guide pin that guides the movable cover while the blade is being raised and lowered, a base portion frame mounted on the track structure ; a blade mounted on the base portion frame by using a linkage mechanism and a cylinder such that the blade can be raised and lowered; a fixed cover supported on the base portion frame and positioned above the linkage mechanism ; a movable cover that covers a gap between the fixed cover and the blade ; and a guide pin that guides the movable cover while the blade is being raised and lowered, wherein the movable cover includes a main surface portion having a lower end connected rotatably with the blade and an upper portion leaning on the fixed cover , the movable cover further including a side surface portion having a slot with which the guide pin engages, and wherein the slot is formed along positions of the side surface portion of the movable cover facing the guide pin when the movable cover rotates by having the upper portion of the main surface portion sliding over the fixed cover in accordance with a raising/lowering operation of the blade , characterized in that the guide pin is supported on the base portion frame , wherein the slot is configured such that the guide pin engages with the slot at a lower end position therein when the blade is raised to a highest position, and wherein the movable cover is configured such that a center of gravity thereof is positioned on a side closer to the base portion frame than to a pivotal point thereof when the guide pin engages with the slot . <EOS>