To provide a current transformer with a heat dissipating tank whose production cost can be reduced.

A bushing 2 is vertically provided on a lower tank. A primary conductor insulated by insulating oil 4 is contained in the lower tank and the bushing 2, and a secondary coil penetrating the primary conductor and insulated by the insulating oil 4 is contained in the lower tank. A heat dissipating tank 6 is installed at the upper end of the bushing 2 to dissipate heat of the insulating oil 4. The heat dissipating tank 6 is a press-formed product whose barrel part 6a has its lower flange 6b and its upper flange 6c in one body. The lower flange 6b is connected to the upper end of the bushing 2, and the upper flange 6c is connected to a mount 13' for an oil controller 7.