Maintaining an assistant braker with non motion status when cutting power or maintenance/examining and repairing. The assistant braker control device of passenger conveyer comprises an assistant braker (3), being maintained with non motion status under the condition of supplying force and being exchanged to motion status through stopping power supply; a control part (1), which terminates the power supplied for the assistant braker (3) when inputting detecting signal from a detecting part (4), the detecting part (4) detects whether the moving state of the conveyer chain which connects with multiple treading parts and makes cycle movement is exceptional; an assistant power supply (7), which supplies power for the assistant braker (3) when a detecting signal from the detecting part (4) is not input and the power supplied by a commercial power supply (6) for the control part (1) is stopped.