A current sensor is configured to detect a current flowing through an electrical conductor. The current sensor includes a core and a coil wound around the core. The core has a hollow therein configured to allow the electrical conductor to pass through the hollow. The core substantially has a C-shape having a gap connected to the hollow. The core has a pair of end surfaces facing each other in a facing direction across the gap. The core includes plural split cores joined to one another. Each pair of split cores of the plural split cores adjacent to each other have respective joining surfaces joined to each other. The respective joining surfaces of the each pair of split cores being parallel to the facing direction. This current sensor has a desired sensitivity characteristic.