PURPOSE: To form a uniform photoresist layer even on the surface having irregularity by a method wherein no crystal is formed in the center of rotation of a spinner, the spinner is rotated at high speed by forming the crystal on the part away from the center, and the stripe direction of the irregularity is set in such a manner that it is brought in the radial direction of rotation.

CONSTITUTION: A substrate 3 of a crystal of gallium arsenide is provided on the rotary disc 1 of the spinner having a stopper 11 with which the scattering of crystal is prevented. The rotary disc 1 rotated by a rotating shaft, a number of stripe-formed protruding parts 3' of 100 μm in width, a period of 500 μm and 2000 in height are formed. When crystal is going to be formed on the rotating disc, the direction of stripe is brought in the radial direction of the disc, and a crystal substrate 3 is provided at the position away from the rotating shaft 3 of the rotary disc 1. As a result, the thin film of uniform photoresist can be formed by avoiding the effect of the recessed and the protrusions even on the crystal having stripelike irregularity.