Ballistic one‐dimensional channels are fabricated using a highly resistive region induced by focused Ga ion beam scanning. Both wide and narrow channels are fabricated using this process. Transport characteristics of these channels are controlled by a voltage applied to the Schottky electrode on the channel. The channels show multiple‐step structures in their transport characteristics at low temperature when the gate voltage is varied. This is probably due to the ballistic transport through one‐dimensional quantized electron states. For narrower channels, the number of the observed steps becomes fewer. Instead, the structures are observable at higher temperature.