The Coriolis effect or illusion is a sensation of angular motion in response to an inclination of the head when the head is undergoing a passive rotation. A dummy head including three gyros and three accelerometers was assembled, and was supported with a pivot and four springs to simulate human neck mechanism. The dummy head was tilted on a rotating table and the data obtained by the inertial sensors were analyzed to explain the cause of the Coriolis effect responsible for the illusion. In conclusion, the force acting on the dummy head is proportional to the angular velocity of the rotating table as well as to the linear velocity of the tilting motion. The force is found to be well described mainly by the principle of the Coriolis acceleration.