A motor-driven vehicle includes a first vehicle body with a fixed cantilever disposed at a front end thereof, and a second vehicle body with a fixed post disposed in front of the cantilever, and a connecting device interconnecting the first and second vehicle bodies removably. The connecting device includes a projection extending upwardly from a front end of the cantilever of the second vehicle body, and a spring-biased retaining block disposed movably on the post of the second vehicle body. The retaining block is biased to a position, where the projection is confined between the retaining block and the post so as to prevent relative movement of the first and second vehicle bodies.