A light sensing apparatus of a wearable device includes a metal piece capable of moving between a first far-end position and a near-end position relative to a skin surface, a light sensing unit that emits light to the skin surface and receives the reflected light, a light guide unit that converges scattering angles of the emitted light, and a control unit that is electrically connected with the light sensing unit and the metal piece. The control unit reads a close fit signal or a first response signal when the metal piece is located at the near-end position or the first far-end position, and then, calculates a measured value associated with the heart rate according to the sensed signal, and executes a preset action command according to the first response signal. Thereby, stability and reliability of calculating the heart rate are improved by reducing scattering and interference of the light by the light guide unit and based on the signal feed back by the metal piece without influencingwearable comfort due to adjustment of wearable tightness.一種穿載式設備的光感裝置，包含能夠相對一個皮膚表層在一個第一遠端位置與一個近端位置間移動的一個金屬件、朝該皮膚表層發射光及接收反射光的一個光感單元、 收斂發射光之散射角度的一個導光單元，及與該光感單元、該金屬件電連接的一個控制單元。該控制單元在該金屬件位於該近端位置或該遠端位置時讀取一個緊配合信號或一個第一回應信號，然後，根據該感測信號計算出與心率相關的一個測量值，及根據該第一回應信號執行預設的一個動作指令。藉此，以該導光單元減少光的散射與干擾，及以該金屬件回饋的信號，在不因為調整穿載鬆緊度而影響穿載舒適性的情形下，提升計算心率時的穩定性與可靠性。
