We propose a method of indoor localization using array sensors. This method uses not only the signal strengths of received signals, but also the spatial information of impinging signals on array sensors. The signal subspaces, which include information about the strengths and angles of arrival of impinging signals on the array sensors, are used to identify the location of the terminal. We use the cosines of the principal angles between the signal subspaces of the spatial covariance matrices of the signals received at an array antenna to measure the similarity between signals transmitted from two locations. We conducted an experiment indoors to confirm the validity and effectiveness of our method. The experimental results confirm its effectiveness.