A brake device includes: a brake pedal including a pedal and a lever that rotates about a rotation axis when the pedal is operated; a housing that rotatably supports the lever; a reaction force generator that generates a reaction force to the lever in accordance with a stroke amount of the brake pedal by receiving a force from the lever when the brake pedal is operated; a deformation member including a deformation portion that is deformed by a force received from the lever when the brake pedal is operated in a state where the reaction force generated by the reaction force generator is generated; and a stroke sensor that outputs a signal corresponding to the stroke amount and outputs a value indicating that operation of the brake pedal is abnormal and instructing execution of control for stopping a vehicle when the deformation portion is deformed.