A forged face detecting method includes: acquiring a photorealistic image and an infrared image of a subject on which line beams are projected; extracting face features from the infrared image based on characteristics of a pattern of the line beams projected on the acquired infrared image; and detecting whether or not the infrared image is a forged face based on the extracted face features. Said detecting whether or not the infrared image is a forged face includes: checking whether the extracted face features falls within a preset permission range of face features; determining the infrared image to have the forged face if the extracted face features fall out of the range to acquire an infrared image of the subject again; and determining the infrared image to have a non-forged face if the extracted face features falls within the range to perform face recognition for the photorealistic image.