Abstract: An apparatus for correcting a posture attachable to a desk, including a desk fixing member of which a side surface has a “C”-shape so as to be fixed on an upper plate of the desk and in which an inserting groove is formed along a vertical direction on a rear surface, an attaching member including a desk attaching unit which penetrates an upper surface or a lower surface of the desk fixing member and is attached on the upper plate of the desk, and an attachment-adjusting screw which adjusts a strength of attachment, a height adjusting member, a posture correcting pad, and a rotatable pad connecting member.