Manufacture of multi-ferrule made of glass material, multi-ferrule manufactured by the method and using method for the multi-ferrule

PURPOSE: To provide a manufacture of a multi-ferrule made of a glass material provided with plural cylindrical passages provided with mutually parallel axial lines. CONSTITUTION: A blank 1 provided with a clearly stipulated cross section provided with plural cylindrical bores 2 provided with the mutually parallel axial lines of an inner diameter Di is formed by the glass material. The dimension and diameter Di of the outer side cross section of the blank 1 are decided with relative accuracy at least equal to the relative accuracy respectively requested for the dimension of the outer side cross section of the multi-ferrule 11 to be manufactured and the inner diameter di of the passage 9 of the multi-ferrule and the blank 1 is vertically arranged inside the device of the same type as a fiber formation device for an optical fiber. Tractive force is added to a member 6 during formation at the lower part of the blank 1, it is drawn until an expected outside dimension is obtained, the dimension of the outer side cross section of the member 6 during manufacture is adjusted, the given length of the manufactured member 6 is cut and thus, the multi-ferrule 11 of the selected length is obtained.