A method for manufacturing a chip constituted by a functional device formed on a substrate comprises a functional device forming step of forming the functional device on one main face of a sheet-like object to be processed made of silicon; a first modified region forming step of converging a laser light at the object so as to form a first modified region along the one main face of the object at a predetermined depth corresponding to the thickness of the substrate from the one main face; a second modified region forming step of converging the laser light at the object so as to form a second modified region extending such as to correspond to a side edge of the substrate as seen from the one main face on the one main face side in the object such that the second modified region joins with the first modified region along the thickness direction of the object; and an etching step of selectively advancing etching along the first and second modified regions after the first and second modified region forming steps so as to cut out a part of the object and form the substrate.