In a fabrication method of a microstructure array, such as a mold for forming a microlens array, a first insulating mask layer is formed on a conductive portion of s substrate, an array of openings for the microstructure array and at least an opening for an alignment marker are formed in the first insulating mask layer during a common process to expose the conductive portion of the substrate at the openings, and first plated or electrodeposited layers are grown in the openings and on the first insulating mask layer using the conductive portion of the substrate as a cathode. The opening for the alignment marker is surrounded by the array of openings for the microstructure array, and a pattern of the opening for the alignment marker is determined such that a current density distribution at the time of electroplating or electrodeposition can be oppressed.