A high-sensitive magnetometer has two SQUIDs each comprising a superconducting loop with one or more Josephson junctions and also has a coil comprising a continuous loop for providing magnetic flux of input signals to each of the SQUIDs in opposite directions. The magnetic flux of the input signals is detected by sums of output voltages of the SQUIDs. Magnetic flux noises equally applied on the two SQUID are cancelled by the continuous loop and at addition of the output voltages of the SQUIDs, thus large output signals can be obtained because sums of the two SQUID output signals are obtained.