An automatic accident informing apparatus for a two-wheel vehicle is provided which can detect the occurrence of accident with the use of a simple arrangement. The automatic accident informing apparatus for a two-wheel vehicle includes an accident detecting module 3 for detecting an accident of the vehicle and an accident informing module 7 arranged responsive to the occurrence of the accident detected by the accident detecting module 3 for informing an external party(s) of the accident. The accident detecting module 3 includes an inclination sensor 2 for measuring the inclination angle of the vehicle and an accident judgment unit 340 for judging that the vehicle met with the accident when the inclination of the vehicle remains higher than a predetermined degree throughout a specific length of time.