A bifunctional automatic luminous device for tyre is composed of a base with a battery bay for containing a battery in it, a circuit board on the base and having a luminous element on its top surface, a conductive ring for respectively connecting them to both electrodes of luminous element, the conductive ring setin the containing space and also for electric connection to conducting wire rings, and a conductive elastomer fixed on the circuit board and electrically connected to the conducting wire ring. When the tyre is rotating, the conductive elastomer is centrifugally deflected to contact the conductive ring, so generating light by the luminous element. |