To surely prevent cavitation and hunching by coping with and any operating conditions and to simply perform adjusting work in a large and small two-type automatic pressure regulating valve.

A large diameter valve element 5 contacts and separates with respect to a large diameter valve seat 4 of the central part of a valve body 1 to open and close a large diameter valve part. A water passing hole 6 is located at the central part of the large diameter valve element 5. A small valve element 8 contacts and separates with respect to the upper end of a small diameter valve seat 7 to open and close a small diameter valve part. Water passing control bodies 21, 22, 24 are clipped between the large diameter valve element 5 and the top surface plate 11 and fixed with bolts 12. A plurality of types of the water passing control body are provided and selectively used according to operating condition.