A foldable pedal apparatus of an autonomous traveling vehicle, is configured so that a pedal pad is popped-up by moving toward a driver to be exposed to enable an operation of the pedal pad by a driver in a manual driving mode situation in which the driver directly drives the vehicle, and the pedal pad moves forward and is in close contact with a vehicle body panel to disable the operation of the pedal pad by the driver in an autonomous traveling mode in which the driver does not directly drive the vehicle, facilitating a hidden state where exposure toward the driver is blocked.