A method of producing a mold having an uneven structure and a mold for an optical element are provided. The method includes forming on a nickel substrate a mixed film using nickel and a material which phase separates from nickel simultaneously, the mixed film including a plurality of cylinders including nickel as a component thereof and a matrix region including the material which phase separates from nickel as a component thereof and surrounding the plurality of cylinders; and removing the matrix portion from the mixed film by etching to give a mold including nickel or a nickel alloy. The uneven structure is disposed in plurality on the substrate, and a pitch of the uneven structure is within a range of 30 nm or more and 500 nm or less and a depth of the uneven structure is within a range of 100 nm or more.