PURPOSE:To obtain a short gate MESFET having high performance by disposing the second source and drain regions having lower carrier density than the first source and drain regions between a gate electrode, and the first source region and the drain region respectively. CONSTITUTION:Source and drain regions are formed double and to be self- aligned with a gate electrode, the second source and drain regions 14, 14' of the gate electrode 3 side have relatively low carrier density and shallow depth, the first source and drain regions 4, 4' of the side separated from the gate electrode have high carrier density to form a high performance MESFET having small short channel effect, and low source resistance. The regions 14, 14' are formed by ion implanting at 15 with the electrode 3 as a mask, and the regions 4, 4' of higher carrier density than the regions 14, 14' are separated from the electrode 3 by ion implanting at 9 with the side wall 16 formed on the side of the electrode 3 as a mask. Thus, a high performance MESFET is obtained.