In a work machine, as a regeneration need determining unit determines that a collecting unit needs to be regenerated, a load control unit causes an increase in load on an engine by controlling a pressure accumulating unit so as to accumulate pressure oil attributable to an output of the engine in the pressure accumulating unit as pressure energy from the hydraulic pump; and once the pressure energy is accumulated to a level matching a pressure accumulation upper limit at the pressure accumulating unit, the load control unit causes the increase in the load on the engine by controlling a power storage unit so as to store electric energy of power generated at a generator attributable to the output of the engine in the power storage unit.