PURPOSE: To apply developer all over a substrate without waste by making an opening length of a nozzle part smaller than a width of a substrate and by providing a pair of flat surface parts to both ends of the nozzle part.

CONSTITUTION: An opening length A of a slit nozzle 20 is a little smaller than a breadthwise direction length B of a substrate 3; however, developer flowing out of the slit nozzle 20 spreads to a side of the substrate 3 due to a flat surface part 24 and is applied all over the substrate 3. In the process, applied developer is hard to protrude from the substrate. The flat surface part 24 is provided to enlarge liquid flowing out of the slit nozzle 20 in widthwise direction by a capillary phenomenon in a clearance between the substrate 3 and the flat surface part 24. Thereby, even if an opening length A of the slit nozzle 20 is smaller than a width of the substrate 3, developer reaches an end part of the substrate 3 without failure. Developer can be applied all over a substrate without waste in this way.