A method for forming fine patterns in a semiconductor device includes forming an etch stop layer and a sacrificial layer over an etch target layer, forming photoresist patterns over the sacrificial layer, etching the sacrificial layer by using the photoresist patterns as an etch barrier to form sacrificial patterns, forming spacers on both sidewalls of the sacrificial patterns, removing the sacrificial patterns, and etching the etch stop layer and the etch target layer by using the spacer as an etch barrier.