To improve the reliability of slip rings by securing waterproofing of the slip rings, which is provided between a revolving super structure and an undercarriage and disposed below a center joint, in an electric drive type construction machine.

An electric drive type construction machine 100 includes an undercarriage 2 and a revolving super structure 15 disposed so as to be revolvable above the undercarriage. On a revolution center line of the revolving super structure and between the revolving super structure and the undercarriage, a center joint 27 and a current collector 30 are disposed on an upper side and on a lower side, respectively. The current collector has a plurality of slip rings 35 and a plurality of brushes 356 provided corresponding to the slip rings and coming in slide contact with the slip rings. A wiring 55 of a power feeding system for feeding current to the slip rings penetrates vertically through the inside of an inside cylindrical body 51 of a center joint. Above the center joint, waterproof means 61 is provided for preventing rainwater from entering from the upper end face of the center joint.