An anti-tilt apparatus is provided in the present invention, in which a frame of a vehicle is locked or released for tilt by a locking mechanism controlled according to the vehicle moving status. In addition, the present invention further provides a frame structure of a tilt vehicle wherein the anti-tilt apparatus and an independent suspended wheel set with a tiltable frame are combined together for maintaining certain comfort, good tracking capability and driving safety while the vehicle is moving and swerving. The anti-tilt apparatus of the present invention functions to lock the tiltable frame while the vehicle is operated in low speed or stop and functions to make wheels simultaneously inwardly incline for providing a tilt capability while the vehicle is swerving in high speed so as to increase higher stability and anti-turnover capability of the vehicle.