In situations such as endoscopic surgeries, a leader cannot use their hands to instruct the other surgeons to perform a task on the monitor because he/she must use both hands to control the surgical equipment. Although there are several pointing methods such as eye gaze tracking, these methods are not suitable for endoscopic surgeries, where optical sensors (e.g. infrared sensors) cannot be used due to the existence of physical obstacles in the operating theater. Therefore, an assisting pointing device apparatus that directly measures the behavior of users and is not based on hands is specifically needed. To tackle this problem, we built a pointing device that measures the tilt angle of a user's head by gyro and acceleration sensors. Furthermore, we evaluated the performance of our device compared to that of a mouse using statistical analysis based on Fitts' law and other commonly used parameters. We considered a mouse as a benchmark to clarify the limitations and possible usage of our device. We found that, although it does not perform as good as a mouse, our device can still suitably perform as an assisting device for limited usage such as for tracking pre-defined lines.