To provide an air-core reactor and its disassembling and transporting means within can greatly reduce the transportation mass.

This air-core reactor is composed of a frame-shaped magnetic shield A and a coil B, which is arranged in the magnetic shield A. The magnetic shield A is composed of an upper horizontal part 1 and a lower horizontal part 2, and a right vertical part 3 and a left vertical part 4, which are formed by stacking silicon steel sheets and rectangular cross section. The upper horizontal part 1 and lower horizontal part 2, and right vertical part 3 and left vertical part 4 are integrated into square-shaped units 6a and 6b. Those units 6a and 6b are provided so that they can be split into two, in the stacking direction of the silicon steel belts. The split units 6a and 6b are put in a transport tank 7 and are transported.