A projector apparatus has a projection device for projecting an image onto a projection surface; at least two displacement sensors for detecting horizontal displacements of the projector apparatus, the displacement sensors being spaced a predetermined distance from each other; a rotational angle calculator for calculating a rotational angle of the projector apparatus in a horizontal plane using the predetermined distance and the horizontal displacements, the horizontal displacements being detected by the displacement sensors; and a distortion corrector for correcting distortion of the image by using the rotational angle, the image being projected by the projection device, wherein the rotational angle is calculated by the rotational angle calculator as a horizontal corrective angle.