To provide a flexible pipe of a long extending distance usable even at a temperature lower than 100°C without deteriorating a heat insulation characteristic.

This flexible pipe is comprises an inner corrugated metal pipe 4, an outer corrugated metal pipe 5 arranged with a distance to the inner pipe 4, a spacer, and a heat insulating material 9 between the inner pipe 4 and the outer pipe 5, and pressure inside an annular gap 6 between the inner pipe 4 and the outer pipe 5 is lower than the atmospheric pressure. The spacer is composed of two ropes 7,8, made of a fiber reinforced plastic, wound on the inner pipe 4 to get reverse each other in their wound direction, in the case of the flexible pipe. The heat insulating material 9 is a fleece material, and the pressure inside the annular gap is between 10-3 and 10-1 mbar.