1. A method of detecting a skin-colored area using a variable skin color model, comprising: a first stage of extracting an initial skin-colored area from an input image using a skin color model, the initial skin-colored area being repeatedly extracted by adjusting a threshold value, which is a criterion for selection of a skin-colored area, until a ratio of a size of the extracted skin-colored area to a size of the entire input image becomes less than a predetermined value; and a second stage of extracting a skin-colored area by applying the threshold value determined in the first stage to the skin color model, the skin color model being modified by analyzing characteristics of object regions and noise regions of the skin-colored area.