While a regular parallel confocal optical system, including a micro lens array placed as an object lens, is employed, a micro lens array, formed as a concave lens, is paired with a micro lens array, formed as a convex lens, to extend an individual lens focal distance of the micro lens arrays to a necessary level for measurement on the height of teeth. An object lens array is formed for confocal measurement to extend a focal distance and widen the scope of measurement. When a three-dimensional tooth data measurement is conducted, based on the extended focal distance and widened scope, the intraoral scanning device is not attached to the teeth and the measurement is able to be conveniently conducted at various angles. The object lens array, comprising the concave micro lens array and the convex micro lens array, is placed on a single-axial linear reciprocating part or a pinhole part in a light receiving part of an image sensor is placed on the single-axial linear reciprocating part to be moved as much as the measurement scope, and thus, when each confocal light source, emitted to the teeth during one linear movement, is located in a focal distance f, the teeth are sensed by the image sensor with the brightest level, and at this moment, a depth value of the teeth is determined based on a position of the linear movement to automatically obtain a three-dimensional shape of the teeth. As such, the formation of the confocal optical system, which is simple and universal and classified into an object optical system, a beam splitter, a light source system, and a sensor optical system, is still able to be employed while at the same time a focal distance for the measurement of a subject can be extended from several millimeters to scores of millimeters, and thus, proper measurement scope is set and three-dimensional measurement is automatically conducted.마이크로렌즈어레이가 대물렌즈로서 위치하는 보편적인 병렬 공초점 방식의 광학계를 사용하면서도 마이크로렌즈어레이의 개별 렌즈 초점거리를 치아 높이값 측정에 필요한 수준으로 확장하기 위해 볼록렌즈(Convex Lens)로 구성된
