PURPOSE: To close a valve port by low closing force and to certainly achieve valve function even in any posture, by forming the energizing means of a valve apparatus from a leaf spring having a specific shape and the cam part engaged with the other end of said leaf spring.

CONSTITUTION: A primary valve 30 is prescribed by an energizing means 28 consisting of a first valve box 20, a first valve body 24a, a second leaf spring 24e and a first cam part 26. The cam part 26 formed to the inner surface of the first valve box 20 in a state built up in a mountain shape is engaged with the first contact part 24f of the first leaf spring 24e in such a state the first valve body 24 is received in a first valve chamber 20d. Therefore, the first valve body 24a is energized by elastic force based on the bending of the first leaf spring 24e so as to be closely contacted with a first valve seat 20b and a valve port 20c is closed by predetermined closing force. In the same way, thus mentioned valve apparatus can be used as a secondary valve.