PURPOSE: To make a pit edge sharp and to increase the flatness of the surface of a photoresist layer by specifying a first developing time, a second developing time and the concentration of an alkalike developer.

CONSTITUTION: In a first developing device 2 for a developing apparatus 1, the surface layer of a positive photoresist layer is developed for a first prescribed time by means of an alkaline developer whose concentration has a range of a normality of 0.17 to 0.19N, and the surface layer is developed down to a prescribed depth. Then, in a first rinsing and drying device 3, the photoresist layer is rinsed and processed, and its developing operation is stopped temporarily so as to be dried. Then, in a second developing device 4, the positive photoresist layer is developed, by an alkaline developer, down to a prescribed developing finish depth for a second prescribed time which is longer than the first prescribed time. In addition, it is desirable that the first prescribed time is 10 to 60 seconds and that the second prescribed time is 100 to 300 seconds.