The present invention relates to an etching solution for a multilayer thin film containing a copper layer and a molybdenum layer, and a method of etching a multilayer thin film containing a copper layer and a molybdenum layer using the etching solution. There are provided an etching solution for a multilayer thin film containing a copper layer and a molybdenum layer, including (A) an organic acid ion supply source containing two or more carboxyl groups and one or more hydroxyl groups in a molecule thereof, (B) a copper ion supply source and (C) an ammonia and/or ammonium ion supply source, the etching solution having a pH value of from 5 to 8, and an etching method using the etching solution.