To eliminate necessity to employ a filter, prevent secondary diffusion to an environment by harmful material particles and increase in mounting places, and satisfy transport limit height of a facility.

A wet capture device for particulate matters or the like included in exhaust gas black smoke is mounted on the upper surface or the lower surface of a diesel engine. Exhaust gas cleaning water including particulate matters or the like included in black smoke is feeded to a mixing plant of solidification agent such as cement milk. The exhaust gas cleaning water is utilized as a part of mixing water added to the solidification agent such as cement, which is a solidification agent to fix a tip supporting bulb and a pile periphery of a buried pile and to form the ground improvement/underground continuous wall or the like.