An intra-oral scanner includes an optical output unit; an optical output control unit to rotate the optical output unit along a first reference axis or moves the optical output unit so as to control an emission position of the output light; an optical system to reflect the output light with the emission position controlled by the optical output control unit to a tooth or teeth being scanned; an optical system driving unit to rotate the optical system along a second reference axis so as to control a reflection angle of the output light; a guide; an optical sensing unit to sense the light reflected by the optical system and convert the sensed light into an electrical signal; and a data transmitting unit to transmit information to a three-dimensional data generating unit to generate a three-dimensional scanning model for the tooth or teeth being scanned.