To provide an accurate vehicle behavior detector for detecting behavior of a vehicle.

A vehicle behavior detector 10 obtains detection information from autonomous sensors 13 to 16 to detect a change in vehicle behavior. The detection information is calibrated based on position, bearing, and vehicle speed information obtained from a GPS receiver 12. For example, the vehicle behavior detector 10 calibrates detection information obtained from the vehicle speed sensor 16 and the angular speed sensor 13 with a Kalman filter process. It is difficult to use only the autonomous sensors 13 to 16 to calibrate characteristics changes due to individual sensor differences, environmental changes, and aged deterioration. With using GPS information for calibration, the vehicle behavior detector 10 can accurately detect the vehicle behavior. The accuracy is improved for detection information itself to be output from the vehicle behavior detector 10 to external apparatuses 20 to 80. Using this calibrated detection information, the external apparatuses 20 to 80 perform processes appropriately.