A spring-supported electric contact device including a track mounting sapce in a lower part of a vehicle body for a flexible track passing through, a seesaw plastic frame pivotably fastened in an open chamber in the vehicle body beneath the track mounting space and having one end supported on a conical spring, an electric contact assembly consisted of two spaced pairs of contact nails electrical connected to the motor drive by an electric wire and fastened to the seesaw plastic frame and constantly disposed in contact with respective metallic electrical conductor strips on the flexible track to connect DC electricity supplied by a DC adapted from city power to the motor drive.