A current sensor includes: a housing that holds a busbar to which a current is applied and a core arranged around the busbar; a circuit board fixed to the housing in the state of being arranged to face the housing; and a detection element for detecting the current; wherein the detection element has an element main body held in the housing and plural connection terminals fixed in through-holes in the circuit board, and a plate-like member provided with guide holes in which the connection terminals are inserted and which have a diameter reduced from the side of the housing toward the side of the circuit board is provided on a surface facing the housing, of two surfaces of the circuit board.