Two sets of assemblies (2a, 2b) are arranged such that a diesel particulate filter device (3) of the assembly (2a), a selective catalytic reduction device (4) of the assembly (2a), a selective catalytic reduction device (4) of the assembly (2b), and a diesel particulate filter device (3) of the assembly (2b) are located next to each other in this order. Exhaust tubes (6) are provided to extend upward from gas outlets (6a) of the selective catalytic reduction device (4) of the assembly (2a) and the selective catalytic reduction device (4) of the assembly (2b). The two exhaust tubes (6) are located on a virtual plane (E) orthogonal to longitudinal directions (B1, B2) of the selective catalytic reduction devices (4) of the assemblies (2a, 2b). Thereby, an air intake position for an engine (10) can be easily set to a position from which exhaust gas from the engine (10) is less likely to be taken in, in a configuration provided with two sets of assemblies (2a, 2b).