Disclosed is a method of manufacturing a field effect type compound semiconductor device in which leakage current of a device is decreased and breakdown voltage is enhanced. The method of manufacturing a field effect type compound semiconductor device includes: stacking an active layer and an ohmic layer on a substrate and forming a first oxide layer on the ohmic layer; forming a mesa region in predetermined regions of the first oxide layer, the ohmic layer, and the active layer; planarizing the mesa region after forming a nitride layer by evaporating a nitride on the mesa region; forming an ohmic electrode on the first oxide layer; forming a minute gate resist pattern after forming a second oxide layer on a semiconductor substrate in which the ohmic electrode is formed and forming a minute gate pattern having a under-cut shaped profile by dry-etching the first oxide layer, the nitride layer, and the second oxide layer; forming a gate recess region by forming a head pattern of a gamma gate electrode on the semiconductor substrate; and forming the gamma gate electrode by evaporating refractory metal on the semiconductor substrate in which the gate recess region is formed.