<p>Analyzation of the rowing motion of a boat is necessary for improving athlete's rowing technique. In this research, a system is developed to measure the rowing motion only by attached the sensors on the boat and the oars. A distance sensor and two IMU sensors are used to measure the motion of the seat, oar, and boat. From the measured data, the movement of the seat and oar can be calculated on the boat. In the evaluation experiment, we test the measurement system on a rowing machine. The accuracy is evaluated by comparing the measured data that obtained from the developed system and the optical motion capture system.</p>