A brake pedal apparatus designed to prevent injury to a driver caused by the brake pedal apparatus crashing toward the ankle of the driver. A pedal arm assembly has a first pedal arm connected to the body of a vehicle. A second pedal arm has an upper end that is rotatably connected to a lower end of the first pedal arm and a lower end that is provided with a pad to which a load is applied by a driver. A driving part generates torque for rotating or fixing the second pedal arm with respect to the first pedal arm and a controller controls the driving part.