Left and right first and second vertical plates 11, 12, and a partition plate 13 are provided on an upper frame 7. The space above the upper frame 7 is divided into a front section S1 and a rear section S2 by the partition plate 13. A cabin 8 is provided on the left side in the front section S1, and a hydraulic oil tank 16 is provided on the right side in the front section S1. A hydraulic pump 15 is provided on the left side in the rear section S2. A pump suction pipeline 24 is connected from the hydraulic pump 15 in the rear section S2, is entered into the front section S1 while passing through the first vertical plate 11 and the partition plate 13, without passing below the cabin 8, and is connected to the hydraulic oil tank 16. Further, a cover plate 30 is fixed to the outer periphery of the pump suction pipeline 24. A partition-plate-side through-hole 29 is covered, and simultaneously, the pump suction pipeline 24 is supported by attaching the cover plate 30 to the partition plate 13.