Magnetic field angle measurement apparatus and angle-measuring device that uses them

In a magnetic field angle detection device and a rotation angle detection device using a tunnel magnetoresistance element, a magnetic field angle detection device and a rotation angle detection apparatus are provided in which the precision of the measured angle is even then not deteriorated when the MR ratio of the tunnel magneto-resistance element increased is. In the magnetic field angle measurement device containing a magnetic field angle detection circuit and a magnetic sensor with a tunnel magneto-resistance element having a fixed magnetic layer, the magnetic field angle detection circuit, a power supply unit that outputs a constant voltage as a bias voltage to the tunneling magneto-resistance element of the magnetic sensor, and a current detection unit which detects an output current of the tunnel magneto-resistance element on. The accuracy of the measured angle of the magnetic field angle detection device and the rotation angle detection apparatus is improved in that the tunnel magneto-resistance element current is measured while the terminal voltage of the tunnel magneto-resistance element is held constant with the input impedance of the current detection unit of zero.