In an optical transmission node network in which a first optical transmission node is connected with a second optical transmission nodes through an optical fiber cable and automatic optical output (APSD: Automatic Power Shut-Down) control is activated, after the APSD control is brought into an inhibited status, if an optical conduction to the second optical transmission node is detected, the APSD control inhibited status is canceled. In this way, if an optical transmission fiber is resorted (reconnected) after optical output power measurement or the like is carried out, the APSD control inhibition status (invalid status) is canceled for automatically restoring the APSD control activated status. Thus, optical output can be prevented from being inadvertently emitted at a high energy level from the optical fiber cable.