1. A user hand detecting device for detecting a user's hand region, comprising: an image acquiring unit configured to acquire a depth image and a color image obtained by imaging a user hand; a first mask image extracting unit configured to extract a first mask image from the depth image—the first mask image includes an object within a predetermined distance from an imaging device that has generated the depth image; a second mask image extracting unit configured to extract a second mask image having a preset skin color value among regions corresponding to the first mask image in the color image; a skin color probability image generating unit configured to generate first and second skin color value histogram models in first and second color spaces of a region of the color image corresponding to a color region of the second mask image, and generate a first skin color probability image of the first color space and a second skin color probability image of the second color space from the color image using the first and second skin color value histograms and an algorithm for detecting a skin color region—the first and second color spaces are different from the color space of the color image; and a hand region detecting unit configured to combine at least two of the first skin color probability image, the second skin color probability image and the second mask image and detect the user's hand region.