An information concealing device comprises a mask means for prompting the user to specify a secret area in an input image, a secret area specifying means for generating image data describing the image of the specified area in the input image and describing an area other than the specified area in a single color, an encoding means for converting the image data, which describes the image of the specified area in the input image and describes an area other than the specified area in a single color, to image data describing a code, and an embedding means for generating the image data of an image describing the specified area in the input image in a single color and embedding the code into the image.