Abstract: An apparatus and a method for measuring a dimension based on a 3D point cloud data are provided to measure various dimensions for a target having a difficulty when the dimension of the target is measured using a measurement tool, such as a tape measure or a protractor. A method for measuring a dimension based on a three-dimensional (3D) point cloud data, includes receiving selection of a specific item from a dimension item list, acquiring 3D point cloud data for a target with respect to each continuous scene by scanning the target, setting a reference point for measuring the dimension whenever a marker displayed on a screen is selected during the scanning of the target, and calculating the dimension corresponding to the selected item, based on the 3D point cloud data, which is acquired during the scanning, and one or more reference points set during the scanning.