A gas separation asymmetric membrane includes a porous layer having gas permeability; and a compact layer having gas separation capability which is formed on the porous layer in which the gas separation asymmetric membrane is formed using a polyimide compound which has a structural unit represented by Formula (I) and at least one structural unit selected from a structural unit represented by Formula (II) or a structural unit represented by Formula (III) and in which the viscosity, at 25° C., of a solution obtained by dissolving the polyimide compound in N-methylpyrrolidone at a concentration of 5% by mass is in a range of 2.2 to 22.0 mPa·sec, in the formula, X1 represents a group having a structure represented by Formula (I-a) or (I-b).