Abstract: A high-pressure tank comprising: a resin liner for a high-pressure tank including at least one opening portion; an aluminum mouth portion attached to the opening portion; and a reinforcement layer formed on an outer surface of the liner, wherein an aluminum oxide coating is formed on a surface of the aluminum mouth portion, the aluminum oxide coating includes a porous surface layer in which columns with an average height of 10 to 100 nm are arranged in a dispersed state, an average value of a percentages of the protruding portion area of the columns in randomly sampled 400 nm square visual fields of the porous surface layer is 5.0 to 26.0%, and an average value of the numbers of the columns in randomly sampled 400 nm square visual fields of the porous surface layer is 500 to 2000.