An electrical power measurement device (1,2) for measuring electrical power consumed in a circuit to be measured including a power source, a load, and a pair of electric wires comprising a first electric wire and a second electric wire connecting the power source with the load, the electric power measurement device (1,2) comprising: a pair of connection terminals (12a,12b) for connecting the load in parallel to the power source, a sensor unit including a plurality of sensor parts, each sensor part including a magnetic element in which element terminals (143, 144) are formed at both ends of a magnetic film, a measurement resistor connected to the magnetic element in series, and a detecting means that detects a voltage change of the magnetic element and outputs a voltage component based on the detected voltage change, the sensor part being connected to the circuit to be measured via the pair of connection terminals (12a, 12b), wherein a magnetization easy axis is induced in the longitudinal direction of the magnetic film, the electric power measurement device further comprising: an addition means that adds outputs of the detecting means of all of the sensor parts in the plurality of sensor parts; the electric power measurement device (1,2) characterized in that it further comprises a fixing means that fixes the magnetic elements of the plurality of sensor parts to the first electric wire, at equal distance positions from a virtual axis serving as a position reference at which the first electricwire is arranged, in a direction facing the virtual axis so that the magnetic field from the second electric wire is applied in the substantially film thickness direction of the magnetic elements, wherein the sensor unit is configured with two sets of the sensor parts, and the fixing means fixes the magnetic elements to each of a pair of inclined planes (58a, 58b), wherein each of the inclined planes (58a, 58b) includes a tangential line that extends from a center of the second electric wire towards a surface of the first electric wire when a center of the first electric wire is arranged on the virtual axis, and the second electric wire is fixed adjacent to the first electric wire. a pair of connection terminals (12a,12b) for connecting the load in parallel to the power source, a sensor unit including a plurality of sensor parts, each sensor part including a magnetic element in which element terminals (143, 144) are formed at both ends of a magnetic film, a measurement resistor connected to the magnetic element in series, and a detecting means that detects a voltage change of the magnetic element and outputs a voltage component based on the detected voltage change, the sensor part being connected to the circuit to be measured via the pair of connection terminals (12a, 12b), wherein a magnetization easy axis is induced in the longitudinal direction of the magnetic film, the electric power measurement device further comprising: an addition means that adds outputs of the detecting means of all of the sensor parts in the plurality of sensor parts; the electric power measurement device (1,2) characterized in that it further comprises a fixing means that fixes the magnetic elements of the plurality of sensor parts to the first electric wire, at equal distance positions from a virtual axis serving as a position reference at which the first electricwire is arranged, in a direction facing the virtual axis so that the magnetic field from the second electric wire is applied in the substantially film thickness direction of the magnetic elements, wherein the sensor unit is configured with two sets of the sensor parts, and the fixing means fixes the magnetic elements to each of a pair of inclined planes (58a, 58b), wherein each of the inclined planes (58a, 58b) includes a tangential line that extends from a center of the second electric wire towards a surface of the first electric wire when a center of the first electric wire is arranged on the virtual axis, and the second electric wire is fixed adjacent to the first electric wire. an addition means that adds outputs of the detecting means of all of the sensor parts in the plurality of sensor parts; the electric power measurement device (1,2) characterized in that it further comprises a fixing means that fixes the magnetic elements of the plurality of sensor parts to the first electric wire, at equal distance positions from a virtual axis serving as a position reference at which the first electricwire is arranged, in a direction facing the virtual axis so that the magnetic field from the second electric wire is applied in the substantially film thickness direction of the magnetic elements, wherein the sensor unit is configured with two sets of the sensor parts, and the fixing means fixes the magnetic elements to each of a pair of inclined planes (58a, 58b), wherein each of the inclined planes (58a, 58b) includes a tangential line that extends from a center of the second electric wire towards a surface of the first electric wire when a center of the first electric wire is arranged on the virtual axis, and the second electric wire is fixed adjacent to the first electric wire.