A method for manufacturing a thin and flexible ribbon of superconductor material such as V.sub.3 Sn, V.sub.3 Ge, V.sub.3 Si, Nb.sub.3 Sn, Nb.sub.3 Ge, Nb.sub.3 Si and La-Au having a fine and compact microscopic structure comprises heating raw superconductor material at a temperature within the range between its melting point and 300.degree. C. above the melting point to form a melt having suitable wettability and viscosity; ejecting the melt through a nozzle under a pressure within the range from 0.01 to 1.5 atm. against a cooling surface of a moving substrate such as a rotating drum; and cooling instantaneously and very rapidly a jet flow of the melt on the cooling surface at a cooling rate of 1,000.degree. C. to 1,000,000.degree. C./sec. In order to manufacture the thin elongated ribbon of excellent configuration it is preferable to effect the cooling in a reduced atmosphere. The invention also provides the thin and flexible ribbon processed by the above mentioned process. When an intermetallic compound such as Nb-Si, Nb-Sn, Nb-Ge, V-Si, V-Sn and V-Ge is used as the raw superconductor material a thin and flexible ribbon of superconductor material having essentially a crystalline structure is formed. When La.sub.1-x (Au.sub.y Cu.sub.1-y).sub.x, wherein x>0.9, 0.ltoreq.y.ltoreq.1 is used as the raw superconductor material it is possible to obtain a thin and flexible ribbon of superconductor material having essentially a fine and compact crystalline structure mixed with amorphous of 10 to 90%.