Current sensor

A current sensor comprising:

• a main current path in which a main current flows;
• an auxiliary current path in which an auxiliary current flows;
• a magnetic detection element detecting intensity of a magnetic field in a magnetic detection direction and disposed around a detection target portion which is a part of the auxiliary current path;
• and
• a magnetic shield member disposed to surround the detection target portion and the magnetic detection element,
• wherein the current sensor is configured to measure a magnitude of the auxiliary current flowing through the detection target portion based on the intensity of the magnetic field detected by the magnetic detection element,
• wherein the auxiliary current path branches from the main current path and has a smaller cross-sectional area than that of the main current path,
• wherein a direction in which the main current path extends is set as a first direction, a direction orthogonal to the first direction and extending along a width direction of the main current path is set as a second direction, and a direction orthogonal to the first direction and the second direction and extending along a thickness direction of the main current path is set as a third direction,
• wherein the detection target portion extends at least in the second direction, and
• wherein the magnetic detection element detects the intensity of the magnetic field only in the magnetic detection direction which is orthogonal to the second direction.