A method for an initial activation of a polymer electrolyte fuel cell includes: humidifying a fuel cell stack; performing a small-current driving operation for applying a small current to the humidified fuel cell stack; and performing an activating operation by repeatedly performing an activation cycle a predetermined number of times. The activation cycle includes: a first driving operation for driving the fuel cell stack to output a first predetermined voltage; a first pausing operation for controlling the fuel cell stack in a no-load open-circuit voltage state; a second driving operation for driving the fuel cell to output a second predetermined voltage; and a second pausing operation for controlling the fuel cell stack in the no-load open-circuit voltage state.