A power measuring apparatus for measuring power to be consumed by a load connected to a power supply through a connection line, which comprises: a pair of connection ends for connecting the power measuring apparatus to the power supply in parallel with the load; a sensor element formed by connecting two magnetic film parts with each other between a pair of sensor terminals (1ta, 1tb), wherein the magnetic film parts have a magnetization easy axis induced in a longitudinal direction of a magnetic film and a plurality of electrically conductive films tilted relative to the magnetization easy axis and formed on a surface of the magnetic film, the magnetic film parts respectively have electrically conductive films with different inclination direction from each other, and a center tap electrode is formed at a portion where the magnetic film parts are connected to each other; wherein one of the sensor terminals is connected to one of the connection ends, and the grounded center tap electrode; a measurement resistor with one end connected to the other of the sensor terminals of the sensor element and the other end connected to the other of the connection ends; and a voltage detecting unit for measuring voltage between measurement terminals using the other of the sensor terminals connected with one of the sensor terminals through a resistor, and a grounded point as the measurement terminals; characterised by n bandpass filters arranged to be connected in parallel between the measurement resistor and the voltage detecting unit; and bandpass filter means having a switch capable of selecting n or less of the bandpass filters out of the n bandpass filters. a pair of connection ends for connecting the power measuring apparatus to the power supply in parallel with the load; a sensor element formed by connecting two magnetic film parts with each other between a pair of sensor terminals (1ta, 1tb), wherein the magnetic film parts have a magnetization easy axis induced in a longitudinal direction of a magnetic film and a plurality of electrically conductive films tilted relative to the magnetization easy axis and formed on a surface of the magnetic film, the magnetic film parts respectively have electrically conductive films with different inclination direction from each other, and a center tap electrode is formed at a portion where the magnetic film parts are connected to each other; wherein one of the sensor terminals is connected to one of the connection ends, and the grounded center tap electrode; a measurement resistor with one end connected to the other of the sensor terminals of the sensor element and the other end connected to the other of the connection ends; and a voltage detecting unit for measuring voltage between measurement terminals using the other of the sensor terminals connected with one of the sensor terminals through a resistor, and a grounded point as the measurement terminals; characterised by n bandpass filters arranged to be connected in parallel between the measurement resistor and the voltage detecting unit; and bandpass filter means having a switch capable of selecting n or less of the bandpass filters out of the n bandpass filters.