A semiconductor device having a switch includes a first FET connected to a terminal and a second FET of a stage following that of the first FET. The gate width of the first FET is greater than that of the second FET. A sum of lengths of a source electrode and a drain electrode of the first FET in a direction perpendicular to the gate width of the first FET is smaller than a sum of lengths of a source electrode and a drain electrode of the second FET in a direction perpendicular to the gate width of the second FET.