PURPOSE: To provide the guided power carriage which eliminates the need for an extra braking system, generates large torque in a low-speed range and obtains a stable speed, and travels automatically following up an external guide body such as an operator.

CONSTITUTION: The power carriage consists of a base 1, wheels 8 which support it through axles 6 so that the base can travel, and a power source (DC electric motor 4) which drives the wheels 6 through an interlocking mechanism 7. This carriage is equipped with a frictional non-step speed change gear 2 which has its speed ratio (rotating speed of output shaft 5/ rotating speed of an input shaft 3) 0 included in a speed change range and coupled with the power source by the input shaft 3 and engaged with the interlocking mechanism 7 by the output shaft 5, a speed sensor (L-shaped lever 22) which detects the speed difference between the base 1 and the external guide body, and an operation mechanism (rod 24 and L-shaped crank 18) which operates the speed change element (speed change ring 10) of the frictional non-step transmission 2 on the basis of the output of the speed sensor and automatically adjusts the speed of the base 1 to the speed of the external guide body.