The aim of this research is developing a system that estimates the direction of users by attaching multiple antennas to users. We proposed the method of direction estimation using RSSI of multiple XBees antennas attached to the helmet as a wearable device. In this study, we used a bucket filled with water to simulate the human head and confirmed that direction estimation is sufficiently possible. The result suggests that it is possible to estimate the direction when the antenna is attached on the helmet.