To provide a current sensor which enables reduction in the number of components to be assembled and can cope with mass production.

A current sensor 1 is constituted of an insert component assembly assembled to a sensor component assembly obtained by assembling a magnetic detection element 13 to a bus bar assembly obtained by integrating a bus bar 11 and a core 12, in a state electrically connected to a connector 20, and a housing 2 integrated by inserting the insert component assembly and the insert molding which performs injection molding of a molten resin.