The invention relates to measuring the concentration of a target component in an object. The invention provides a component concentration measurement method including a first step in which light is irradiated onto a measurement object held in a first magnetic field state for detecting the light from the object, a second step in which light is irradiated onto the object held in a second magnetic field state different from the first state for detecting the light from the object, and a third step in which the concentration of the target component is calculated based on the detection results in the first and the second steps. The first magnetic field state may be a magnetic-field-modulated state, while the second state may be a non-magnetic-field-modulated state.
The device of the present invention comprises a ring (1) of a ferrite material and two coils (4, 5) wound around it. A alternating current is fed to one of the coils (4). This current gives rise to an alternating magnetic field within and along the ring, which in turn generates an alternating electric field. A specimen (3) is placed in the alternating electric field. The dielectric properties of the specimen (3) affect the electric field, which in turn induces a magnetic field and generates currents in the coils (4, 5). As the dielectric properties of the specimen (3) depend on its glucose level, the glucose level can therefore be measured by determining a parameter depending on the inductances of the coils.
