An aspect of the present invention provides a passenger protection device that includes, a brake pedal sensor configured to detect the amount by which a brake pedal of a vehicle is operated, a webbing, one end of the webbing fixed to the vehicle, configured to restrain a passenger seated on a seat of the vehicle, a retractor connected to the other end of the webbing, the rector configured to retract the webbing and inhibit of the webbing extraction, and an ECU electrically coupled to the brake pedal sensor, the ECU configured to detect that the brake pedal operation amount detected by the pedal sensor exceeds a first threshold value, the ECU configured to revise the threshold value based on safety related information of the vehicle to control the inhibition of the webbing extraction of the retractor.