An electric power storage device (19) disposed on a revolving frame (6) located closer to an upstream side in a flow direction of cooling air (F) than a heat exchanger (18) is provided on an upper revolving structure (4). The electric power storage device (19) has a box-shaped casing (20) forming an outer wall and a battery module (29) provided in the casing (20) and accommodating an electrolyte. An electrolyte discharge pipe (30) for discharging an electrolyte mist and/or electrolyte injected out of the battery module (29) at abnormality of the battery module (29) to an outside of the upper revolving structure (4) is provided on the casing (20).
