A manual-swinging scooter includes a steering stem with a handle, a fixture extending therefrom, two main frames with treadles outwardly extending from the fixture, and a wheel assembly connected to the fixture and the main frames, respectively. A swingable assembly pivotally disposed between each main frame and frame wheel has a support seat vertically coupled to the main frame, a base with a bevel surface inclinably disposed on the support seat, a rotary shaft pivoting to the support seat, a connecting shaft respectively engaged with the rotary shaft and the frame wheel, and a brace disposed on the connecting shaft for slidably propping against the bevel surface and for the connecting shaft to swing relative to the bevel surface.