The present invention relates to a blade pitch control apparatus for a small size wind power generator. More specifically, the present invention relates to a blade pitch control apparatus for a small size wind power generator configured to accomplish continuous generation by continuously maintaining the necessary rotating force of the blade by systematically operating the ball screw, spinner driver, and pitch angle controller when the rotation number of blades exceeds the reference rotation number by over wind speed, so that the blade pitch is automatically controlled. To this end, the present invention comprises a blade combined with an outer circumference surface of a rotator, rotating by wind; a spinner box installed and fixed in the middle of the front surface of the blade; a ball screw formed with speed control wings at one end in a state positioned in the longitudinal direction in the middle of the spinner box and having screws at the other end; a spinner driver screw-combined with the screw of the ball screw, and moving to the front and back when the rotation number of blades exceeds the reference rotation number by over wind speed or when the wind speed decreases; and a pitch angle controller connected between the spinner driver and blade, folding and unfolding the blade according to the movement direction of the spinner driver to control the pitch angle of the blade.