Magnetic field measuring element, magnetic field measuring device, and magnetic field measuring system

In order to lower a magnetic field measuring element in the height direction thereof while reducing interference, this magnetic field measuring element is characterized by comprising a Superconducting QUantum Interference Device (SQUID) magnetic sensor (1z), a SQUID magnetic sensor (1x) disposed either on a second plane which is perpendicular to a first plane including a coil surface of the SQUID magnetic sensor (1z) and which includes the center of the SQUID magnetic sensor (1z), or in the vicinity of the second plane, and a SQUID magnetic sensor (1y) disposed either on a third plane perpendicular to the first plane and the second plane, or in the vicinity of the third plane, wherein the center of the SQUID magnetic sensor (1x) is present either on a straight line which passes through the center of the SQUID magnetic sensor (1z) and is perpendicular to the first plane, or in the vicinity of said straight line, and the center of the SQUID magnetic sensor (1y) is present in a position displaced from a line joining the center of the SQUID magnetic sensor (1z) and the center of the SQUID magnetic sensor (1x).