The invention provides a magnetic sensor and a manufacturing method for the same. The magnetic sensor includes a semiconductor substrate having Hall elements on a front surface of the semiconductor substrate, a conductive layer formed on a back surface of the semiconductor substrate, and a magnetic flux converging plate formed on the conductive layer. The magnetic flux converging plate is formed on the back surface of the semiconductor substrate through formation of the base conductive layer on the back surface of the semiconductor substrate, formation of a resist on the base conductive layer having an opening for forming the magnetic flux converging plate, formation of the magnetic flux converging plate in the opening of the resist by electroplating, removal of the resist, and removal of a part of the base conductive layer by etching with the magnetic flux converging plate as a mask.