A method for manufacturing a semiconductor device having multi-channels is provided. The method includes etching an active region of a gate region and a device isolation layer of the gate to form a gate recess, forming a first gate buried in a lower portion of the gate recess, forming an active bridge on the first gate for connecting portions of the active region at both sides of the first gate, and forming a second gate on the first gate to cover the active bridge. Therefore, a multi-channel region can be formed.