An amorphous alloy thin band produced by single roll method in which the magnetic characteristics and space factor are improved to excellent levels by regulating the slipperiness on the surface of the amorphous alloy thin band to within a specific range, characterized in that the slipperiness on the surface of the thin band satisfies the following expression; 0.1=F=P/M=1.0, where F is sliding coefficient of friction, P is a force for drawing out a steel plate at an intermediate portion when a weight is imparted to three stacked steel plates from above, and M is a weight (5 kg) from above the steel plate.