An object of the present invention is to provide a magnetic field measuring device capable of obtaining a more detailed gradient magnetic field distribution. A plurality of magnetic sensors each having a magnetoresistive element and a magnetic converging plate disposed at at least one of one end and the other end of the magnetoresistive element, and capable of detecting a magnetic field in three axial directions. A magnetic sensor array configured by three-dimensionally arranging the magnetic sensor cells, a plurality of AD converters that convert analog detection signals output from each of the plurality of magnetic sensors into digital measurement data, and digital measurement data The magnetic field acquisition unit that acquires the digital measurement data from the magnetic field acquisition unit, the spindle sensitivity, the other axis sensitivity, and the calibration calculation unit that calibrates using at least one of the offset, and the digital measurement data is calibrated Provided is a magnetic field measurement device that includes a gradient magnetic field calculation unit that calculates a gradient magnetic field using magnetic field measurement data. [Selection] Figure 8【課題】より詳細な勾配磁場分布を得ることができる磁場計測装置を提供する。【解決手段】各々が磁気抵抗素子と磁気抵抗素子の一端および他端の少なくともいずれか一方に配置された磁気収束板とを有する磁気センサを複数有し、磁場を３軸方向で検出可能な複数の磁気センサセルを三次元に配列して構成される磁気センサアレイと、複数の磁気センサのそれぞれが出力するアナログの検出信号をデジタルの計測データに変換する複数のＡＤ変換器と、デジタルの計測データを取得する磁場取得部と、磁場取得部からのデジタルの計測データを、主軸感度、他軸感度、および、オフセットの少なくともいずれかを用いて較正する較正演算部と、デジタルの計測データを較正した磁場計測データを用いて、勾配磁場を算出する勾配磁場演算部と、を備える、磁場計測装置を提供する。【選択図】図８
