1. A multi-primitive fitting method comprising: acquiring point cloud data by collecting data of each of input points; obtaining a segment for the points using the point cloud data; and performing primitive fitting using data of points included in the segment by: performing a first primitive fitting using points belonging to the segment to produce a fitted primitive, performing a validity check to check a validity of the fitted primitive, determining a number of points belonging to the segment and not belonging to the fitted primitive when the validity check passes, and performing a second primitive fitting using only points belonging to the segment and not belonging to the fitted primitive when the number of points belonging to the segment and not belonging to the fitted primitive is equal to or greater than a threshold value.