An electricity-conducting roller includes a hub joined to a lower end of a frame of a vehicle, and an electricity-conducting roller module; a wheel of the vehicle is fitted on the hub, and the electricity-conducting roller module is fitted to a bottom of the hub, and comprises a fixed supporting member secured to the bottom of the hub, an electricity-conducting roller, a swinging support member pivoted on the fixed support member for holding the electricity-conducting roller in position, and an elastic element to bias the swinging support member downwards in order for the electricity-conducting roller to be in constant touch with the floor; the swinging support member will swing up and down while the vehicle is moving on an uneven floor, thus preventing the electricity-conducting roller from being obstructed by bumps and holes on the uneven floor.