To shorten a track-equipped dolly even if wheels for running are provided in front of and behind the loading space about in the dolly advancing direction in order to lessen the height of the dolly.

A track-equipped dolly is furnished with a loading space 20, a pair of running means 22A and 22B installed capable of revolving consolidatedly within a plane relative to the loading space 20 in positions in front of and behind the loading space about in the dolly advancing direction, and a controller 39. One of the running means 22A is furnished with a left and a right driving wheel 24 coupled together through a differential gear 27 and rolling on rails 21A and 21B and a driving mechanism 25 for driving the driving wheel 24. The other running means 22B is furnished with a left and a right follower wheel indepent of each other and rolling on the rails 21A and 21B and encodes mounted on the respective follwer wheels for generating pulses corresponding to the running distance of the dolly. The controller 39 controls the running of the dolly on the basis of the pulse signals given from the encoders.