A position measuring apparatus comprising: a first irradiating part configured to irradiate a first beam to an object having multiple joints, wherein rigid parts of the object are connected by joints and the first beam evenly covers the entire surface of the object; a second irradiating part configured to irradiate a second beam to the object, wherein the second beam forms a two-dimensional pattern on the surface of the object; a capturing part configured to capture images of the object; a processing part configured to generate a first difference image and a second difference image by processing the images captured by the capturing part, wherein the first difference image is generated according to a difference between an image captured when the first beam is irradiated and an image captured when no beam is irradiated and the second difference image is generated according to a difference between an image captured when the second beam is irradiated and an image captured when no beam is irradiated; an extracting part configured to extract a contour of the object and feature points of bending parts of the joints of the object from the first difference image; a calculating part configured to calculate three-dimensional coordinates of reflection points located on the object based on the second difference image; and a determining or model matching part configured to determine position parameters of the entire object and a joint angle list indicating position parameters of the angles of the joints of the object by matching the extracted contour, the extracted feature points, and the calculated three-dimensional coordinates with respect to predetermined modeled data of the object, wherein the position parameters include a three-dimensional position and a tilt of the object, and the determination part being configured to determine the position parameters by calculating position parameters of a center rigid part of the object, and by calculating position parameters of rigid parts connected to the center rigid part based on the calculated position parameters of the center rigid part and modeled data, and, when uncalculated rigid parts are connected to rigid parts whose position parameters are already calculated, obtaining the position parameters of the uncalculated rigid parts based on the calculated rigid parts. a first irradiating part configured to irradiate a first beam to an object having multiple joints, wherein rigid parts of the object are connected by joints and the first beam evenly covers the entire surface of the object; a second irradiating part configured to irradiate a second beam to the object, wherein the second beam forms a two-dimensional pattern on the surface of the object; a capturing part configured to capture images of the object; a processing part configured to generate a first difference image and a second difference image by processing the images captured by the capturing part, wherein the first difference image is generated according to a difference between an image captured when the first beam is irradiated and an image captured when no beam is irradiated and the second difference image is generated according to a difference between an image captured when the second beam is irradiated and an image captured when no beam is irradiated; an extracting part configured to extract a contour of the object and feature points of bending parts of the joints of the object from the first difference image; a calculating part configured to calculate three-dimensional coordinates of reflection points located on the object based on the second difference image; and a determining or model matching part configured to determine position parameters of the entire object and a joint angle list indicating position parameters of the angles of the joints of the object by matching the extracted contour, the extracted feature points, and the calculated three-dimensional coordinates with respect to predetermined modeled data of the object, wherein the position parameters include a three-dimensional position and a tilt of the object, and the determination part being configured to determine the position parameters by calculating position parameters of a center rigid part of the object, and by calculating position parameters of rigid parts connected to the center rigid part based on the calculated position parameters of the center rigid part and modeled data, and, when uncalculated rigid parts are connected to rigid parts whose position parameters are already calculated, obtaining the position parameters of the uncalculated rigid parts based on the calculated rigid parts.