Mounting structure for NOx reduction device for construction machine

A mounting structure for an NOx reduction system for a construction machine having an engine compartment, a counterweight arranged adjacent the engine compartment at a rear position of a body to maintain stability of the body, an engine and a hydraulic pump drivable by the engine, said engine and hydraulic pump being arranged in the engine compartment,

• said NOx reduction system including a PM collection filter to be arranged in an exhaust passage of the engine to collect suspended particulate matter contained in exhaust gas from the engine, a reduction catalyst for reducing and purifying nitrogen oxides contained in the exhaust gas from the engine, a reducing agent spray device for spraying a reducing agent into the exhaust passage of the engine, a reducing agent feeder for feeding the reducing agent to the reducing agent spray device, and a reducing agent storage tank for storing therein the reducing agent to be guided to the reducing agent feeder, wherein:
• a recessed section, of which a top side opens toward a top of the counterweight, is formed at a side of the engine compartment in an upper portion of the counterweight,
• the reduction catalyst is arranged in the recessed section, and
• the PM collection filter is arranged in the engine compartment so that the PM collection filter is communicated with the reduction catalyst via a piping.