The transient photocurrent response of biodevice consisting of chlorophyll a Langmuir Blogell film was investigated. Chlorophyll a LB films I-To deposited onto the ITO coated. glass. To confirm, the film formation, surface analysis of chlorophyll a, LB film was done by the -measurements of scanning tunneling nricroscopy. Metal/insulator/metal structured biodevice was constructed by depositing aluminum, onto ilia chlorophyll a LB film surface. To investigate the photoelectric response, action spectrum was measured at various wavelenghts. various wavelengths by xenon lamp irradiation, Finally, Ilia photohinduced charge transfer roles were measured using the transient photocurrent decay times. The proposed biodevice consisting of chlorophyll a could. be applied to construct the molecular photonic device due to ilia photoinduced current flow.