The invention relates to a scanner for an oral cavity comprising: an optical output unit for outputting a line laser beam a first optical system for reflecting the line laser beam output from the optical output unit to a scanning target tooth an optical sensing unit for sensing the line laser beam reflected again by the first optical system after reflected from the scanning target tooth and a control unit for controlling operations of the optical output unit and the first optical system. The control unit controls the reflection angle and position of the first optical system.