Abstract: Provided is a reference mirror converter of a Linnik interferometer in which a first object lens 30 focuses light emitted from a beam splitter 20 on a reference mirror 40, a plurality of reference mirrors 40 reflects light incident from the first object lens 30, a plurality of reference mirrors 40 is disposed on a plurality of reference mirror brackets 45, respectively, the plurality of reference mirror brackets 45 is disposed on a rotary plate 60 at the same angles, and the rotary plate 60 is rotated using a motor 70 to control a rotation of the rotary plate 60 to select the reference mirror 40 having a reflectivity similar to that of a target 200 to be measured from among the plurality of reference mirrors 40. Accordingly, since a separate state between articles is maintained at all times, adhesiveness between articles packaged with an easily adhesive material may be prevented.