CURRENT SENSOR

PROBLEM TO BE SOLVED: To provide a compact current sensor for contactlessly detecting an AC current with high accuracy, while allowing easy installation when in use.SOLUTION: A current sensor 100 includes a Rogowski coil 40 formed around an opening 30 of a multilayer substrate 20, and composed of a plurality of wiring layers 40a-40c of the multilayer substrate 20 and a connection conductor 70 for electrically connecting the wiring layers 40a-40c, to contactlessly detect an AC current flowing through a conductor 10 that penetrates through the opening 30. The multilayer substrate 20 has flexibility. A slit-like notch 80 for connecting an outer periphery of the opening 30 with an outer periphery of the multilayer substrate 20 is formed in the multilayer substrate 20.