A space surrounded by a partition member (26) partitioning between an engine (8) and a heat exchanger (20), a top plate (21D) of a support frame (21) constituting the heat exchanger (20), and a top plate (13A) of an engine cover (13) is defined as an article accommodating space (30). In addition, an article box (32) where tools necessary for a maintenance operation are stored is accommodated in the article accommodating space (30). Thereby even in a hydraulic excavator (1) of a type having a small swing radius at the rear in which the engine (8) and a counterweight (7) are arranged close to each other, by effectively using a top surface side of the heat exchanger (20), it is possible to secure the article accommodating space (30) for accommodating an article such as the article box (32) in a housing cover (12).