Gallium was deposited on a tip specimen of a field ion microscope by making contact in vacuum. Gallium deposited on a tip area and diffused from the tip shank at 350 to 500 °K was crystallized in the pseudomorphic structure on tungsten. The number of atomic layers of the pseudomorphic gallium was 2 to 3. The sharp helium image of the pseudomorphic gallium appeared at a voltage considerably lower than the helium best‐image voltage for tungsten. The observed high evaporation field of the pseudomorphic gallium, 3.0–4.5 V/Å, may indicate that the gallium atoms in the pseudomorphic state are anomalously strongly bound to the substrate tungsten or are field evaporated as the doubly‐ionized ions. Various superstructures were observed on the {112} areas after heating above 900 °K, but their detailed structures did not depend upon temperature or heating time. An unidentified underlayer may play a dominant role in determining the structure of the superstructures. No clear evidence of alloy formation was noticed in the temperature range 21 to 1500 °K.