The object of the present invention is to provide a polishing apparatus having a grinding member in a compact design that can provide high efficiency for both polishing and dressing operations, and prevents tilting of the grinding member even if the rotation axis thereof is moved away from the outer periphery of the object. A polishing apparatus for an object, comprises: an object holder for holding an object to be polished, such that a surface of the object to be polished faces upward; a dresser disk holder for holding a dresser disk for dressing, such that a dressing surface thereof faces upward; and a grinding member for polishing the object, and for being dressed by the dresser disk, by pressing and sliding the grinding member relative to the object and the dresser disk. Thereby, the surface to be polished and the dressing surface are arranged so as to be coploanar, and the grinding member having an abrasive surface facing downward, is disposed so as to straddle the surface to be polished of the object and the dressing surface of the dresser disk to perform polishing of the surface to be polished and dressing of the abrasive surface of the grinding member.