TWI828873B

This coating device applies, with a prescribed thickness, to a surface of a to-be-processed substrate supported by a substrate support mechanism, a coating liquid discharged through an opening which is formed at a leading end facing the surface of the to-be-processed substrate and which extends in a slit shape in a first direction, the coating device being provided with: a die head mechanism which comprises a pair of inner wall surfaces extending in the first direction opposingly to each other with a prescribed gap therebetween so as to form a flow path through which the coating liquid flows from a storage part, which extends in the first direction so as to temporarily store the coating liquid, toward the opening of the leading end; and an opening width measurement mechanism for measuring a change in the gap between the inner wall surfaces in order to detect a change in the width of the opening in a second direction orthogonal to the first direction.