Fecha de publicación: 27/12/2000 Fuente: Wipo "Sensorization" It is an object of the invention to provide a magnetic sensor apparatus and a current sensor apparatus that exhibit high performance at low costs. A magnetic sensor apparatus comprises a magnetic core (1) having a magnetic saturation property and a sensor coil (2) wound around the magnetic core (1). An end of a detection coil (20) is connected to an end of the sensor coil (2). The other end of the detection coil (20) is grounded. The magnetic sensor apparatus further comprises a drive circuit (3) and a detection circuit (4). The drive circuit (3) has a series resonance circuit part of which is made up of the sensor coil (2). To the sensor coil (2) the drive circuit (3) supplies a resonance current flowing into the series resonance circuit as an alternating current that allows the magnetic core (1) to reach a saturation region. The detection circuit (4) detects a magnetic field to be measured by detecting variations in resonance current flowing through the sensor coil (2).