PURPOSE: To manufacture long stretching wires with excellency in superconductive characteristics by encapsulating a powder of oxide superconductive substance in a metal pipe to yield a superconductive wire, wherein the metal pipe is provided with a spiral cut-in in its longitudinal direction.

CONSTITUTION: Fine powder of Y2O3, BaCO3, CuO is prepared in atomic proportion of Y:Ba:Cu as 1:2:3 and heat treated in O2 atmosphere at 900°C for 12hr so as to yield a provisionally baked substance 2. This oxide of YBa2Cu3Ox in the form of provisionally baked substance 2 is encapsulated in an Ag pipe 1 of 10mm in outs. dia. D and 8mm in ins. dia. d, followed by stretching process until the outs. dia D becomes 1mm. This Ag pipe 1 is provided at its surface with a spiral notch 5 by forming an Ag exposed part 4 in 0.5mm-wide spiral form by means of etching in the dimensions of for ex. the width 8mm and pitch 8.5mm with acrylic coatings 3, which are exfoliated afterward with acetone. This pipe 1 is held in oxygen at 930°C for five hours, followed by another heat treatment at 600°C for 20hr to yield a superconductive wire. This provision of spiral notch on the longitudinal direction will output a wire with excellency in superconductivity.