PURPOSE: To achieve the stability and certainty of a valve closed state by providing a seat part receiving a spherical coating element in a freely rotatable manner to the leading end of a push element and providing an engaging part engaging one end of a spring to the leading end side thereof and engaging the other end of the spring with the stepped part of a leading end holder.

CONSTITUTION: After a spherical coating element 4 is put in a tip 3 from the rear end opening of the tip 3, a push element 5 in which a spring 6 is incorporated in the state engaged with an engaging part 10 at one end thereof is incorporated in the tip 3 and the rear end connection part 3a of the tip 3 is inserted in the leading end port 2a of a leading end holder 2 under pressure until it comes into contact with the stepped part 8 of the bottom of the leading end port 2a. Whereupon, the other end of the spring 6 is engaged with the stepped part 8 of the bottom of the leading end port 2a and the push element 5 is elastically pushed toward the liquid coating port 7 of the leading end of the tip 3 and brings the spherical coating element 4 into contact with the inward mouth edge 7a of the liquid coating port 7 in such a state that the spherical coating element 4 is received in a freely rotatable manner by a leading end seat part 9. By this constitution, the contact state of the spherical coating element 4 with the entire periphery of the mouth edge 7a is stabilized.