Detection of line-of-sight (LOS) has a variety of applications, such as communication tools for elderly or disabled people, assisting drivers, and effective location of traffic signs. To realize such promising applications, the LOS detecting system that does not restrict users' activities and is free from mental stress from the equipment is strongly demanded. In this paper, we propose a novel wearable LOS detection system that affects the users as little as possible both physically and mentally using dye-sensitized photovoltaic devices. The photovoltaic devices are transparent and generate voltage according to the incident light intensity. Arraying the devices on wearable eyeglasses, this system detects the difference in the reflection light from the pupil and the white of the eye and thus, the position of the pupil. This system is wearable as an eyeglass and hence, it does not disturb the activities and the eyesight of users. More importantly, it involves very little physical and psychological stress to users. We fabricated and characterized the photovoltaic device and demonstrated the feasibility of detecting the location of the pupil. We found it possible to meet the required reaction time of 100 ms by reducing the size of the device and to improve the accuracy of detecting the location of the pupil by arraying the devices.