A method for fabricating semiconductor device includes the steps of: forming a first gate structure and a second gate structure on a substrate and an interlayer dielectric (ILD) layer around the first gate structure and the second gate structure; transforming the first gate structure into a first metal gate and the second gate structure into a second metal gate; removing part of the ILD layer between the first metal gate and the second metal gate to form a recess; forming a first spacer and a second spacer in the a recess; performing a first etching process to form a first contact hole; and performing a second etching process to extend the first contact hole into a second contact hole.