The invention discloses a vertical sander. The vertical sander comprises a base, wherein a grinding part and a fixing part are arranged on the base. The vertical sander is characterized in that the grinding part is arranged in the middle of the base; the fixing part is divided into a first fixing part and a second fixing part, the first fixing part and the second fixing part are separately arranged on the two sides of the grinding part, and each of the first fixing part and the second fixing part comprises a rack connected with the base and a transverse plate horizontally arranged on the rack; and the grinding part comprises a first grinding assembly and a second grinding assembly symmetrically arranged, each of the first grinding assembly and the second grinding assembly comprises first sliding rails and grinding boxes arranged on the first sliding rails, the plurality of first sliding rails are arranged on the base in parallel, the grinding boxes are strip-shaped, and openings are formed in the adjacent one side surfaces of the two grinding boxes. The vertical sander has the advantages of being simple in structure, high in use efficiency, low in cost and the like.