PURPOSE: To accurately obtain a fine pattern having stable pattern shape up to the details by producing a photomask by a magnetic printing method.

CONSTITUTION: A magnetic thin film 2 is uniformly formed and stuck on the whole of one side of a filmlike transparent plastic substrate 1, this substrate 1 is fitted to a magnetic printer and a magnetic field is applied to the thin film 2 with a magnetic head 3 in accordance with an image signal to form a residual magnetization pattern (magnetic latent image). A magnetic toner 5 is then attracted to the magnetic latent image area and the residual magnetization pattern is made visible by development. The resulting visible image is fixed by heating, the exposed part of the thin film 2 is removed and the toner 5 is removed. A photomask having a fine pattern of the magnetic thin film 2 is produced. The pattern shape of this photomask is stable.