Disclosed are an etchant which is used for redistribution of a semiconductor substrate having an electrode and which is capable of selectively etching copper without etching nickel; and a method for manufacturing a semiconductor device using the same. Specifically disclosed are an etchant which is used for redistribution of a semiconductor substrate and which contains hydrogen peroxide and citric acid and has a content of hydrogen peroxide of from 0.75 to 12% by mass and a content of citric acid of from 1 to 20% by mass, with a molar ratio of hydrogen peroxide and citric acid being in the range of from 0.3 to 5; an etchant for selective etching of copper which is used for redistribution of a semiconductor substrate and which contains hydrogen peroxide and malic acid and has a content of hydrogen peroxide of from 0.75 to 12% by mass and a content of malic acid of from 1.5 to 25% by mass, with a molar ratio of hydrogen peroxide and malic acid being in the range of from 0.2 to 6; and a method for manufacturing a semiconductor device using such an etchant.