<p>In this heterojunction field-effect transistor, the lengthwise length (L2) of each source electrode (12) is the same as the lengthwise length (L1) of each drain electrode (11). Also, the lengthwise positions of the lengthwise ends (12A and 12B) of the source electrodes (12) coincide with the lengthwise positions of the lengthwise ends (11A and 11B) of the drain electrodes (11). The lengthwise ends (12A and 12B) of the source electrodes (12) do not protrude further outwards in the lengthwise direction than the lengthwise ends (11A and 11B) of the drain electrodes (11), preventing the flow of electrons from becoming concentrated along paths from the ends (12A and 12B) of the source electrodes (12) to the ends (11A and 11B) of the drain electrodes (11).</p>
