In a method for recognizing corners of an angular component, an image of a subject including the angular component is taken and outline pixels of the angular component are detected. Vector sums of first and second position vectors are calculated based on the outline pixels. A reference value having a predetermined magnitude is sampled from the vector sums. A threshold value for detecting corners of the angular component is calculated based on the reference value. The vector sums are sequentially compared with the threshold value in order to judge whether or not the corners thereof are detected according to the comparison result. It will be decided whether an operation of recognizing the corners thereof has succeeded through detecting corners of the angular component. The corners of angular component can be recognized at a high speed through the exact performance of the recognition processes, thereby mounting the components to an accurate position of the printed circuit board.