The present invention relates to a monitoring method and a monitoring apparatus using a camera. According to an embodiment of the present invention, a monitoring method using a camera includes receiving a photographed input image from the camera; detecting an object existing in the input image and positional information of the object; generating a corrected image by correcting a distorted area of the input image; and generating a synthesized image by synthesizing alarm display information which is generated on the basis of the object and the positional information, with the corrected image, and outputting the synthesized image through a display.