The present invention provides a vehicle motion detecting apparatus that can satisfy a required detection accuracy with a simple architecture and at a low cost, and also maintain reliability of an applied external apparatus. The vehicle motion detecting apparatus 100 of the present invention has a motion detecting section 10 that detects a motion of a vehicle and a malfunction detecting section 20 that detects a malfunction of the motion detecting section 10, and is characterized in that the motion detecting section 10 is a 6-axis inertial sensor as the first multi-axis inertial sensor that is capable of detecting accelerations in directions of three axes and angular velocities about three axes.