Dustproof structure for alignment unit

The present invention provides a dustproof structure for an alignment unit, which is suitable as a dust cover for an OAS-type alignment unit. A dust-proof structure for an alignment unit, the dust-proof structure being provided with: a frame in which an opening is formed; and a dustproof film which is spread and supported on one surface side of the frame body so as to cover the opening, the dustproof structure body being provided with at least one of a fixing part for mechanically fixing the dustproof structure body to the alignment unit and a magnet for fixing the dustproof structure body to the alignment unit. 本发明提供适合作为OAS方式的对准单元用的防尘罩的、对准单元用的防尘构造体。一种对准单元用的防尘构造体，该防尘构造体具备：框体，其形成有开口；以及防尘膜，其以覆盖开口的方式铺展支承于框体的一面侧，其中，该防尘构造体具备用于将防尘构造体机械地固定于对准单元的固定部和用于将防尘构造体固定于对准单元的磁体中的至少一者。