A material defect detection system comprising: a magnetic sensor array comprising a plurality of magnetic sensors; and a measurement management device for detecting a material defect in a predetermined region of a metallic equipment using a magnetic field distribution in the predetermined region measured by the magnetic sensor array; wherein the measurement management device comprises: a magnetization direction computer configured to compute a magnetization direction in the predetermined region of the metallic equipment based on the magnetic field distribution measured by the magnetic sensor array; a magnetic dipole density distribution calculator configured to calculate a density distribution of magnetic dipoles in the predetermined region based on the magnetic field distribution measured by the magnetic sensor array and the magnetization direction computed by the magnetization direction computer; and a depth distribution calculator configured to calculate a depth distribution of material defect in the predetermined region based on the density distribution of the magnetic dipoles, characterized in that the magnetization direction computer is configured to integrate a magnetic field distribution in a normal direction of the predetermined region among magnetic field distributions measured by the magnetic sensor array on a straight line in each of perpendicular directions with respect to the normal direction, and computes the magnetization direction based on integrated values obtained from integration on the straight line. a magnetic sensor array comprising a plurality of magnetic sensors; and a measurement management device for detecting a material defect in a predetermined region of a metallic equipment using a magnetic field distribution in the predetermined region measured by the magnetic sensor array; wherein the measurement management device comprises: a magnetization direction computer configured to compute a magnetization direction in the predetermined region of the metallic equipment based on the magnetic field distribution measured by the magnetic sensor array; a magnetic dipole density distribution calculator configured to calculate a density distribution of magnetic dipoles in the predetermined region based on the magnetic field distribution measured by the magnetic sensor array and the magnetization direction computed by the magnetization direction computer; and a depth distribution calculator configured to calculate a depth distribution of material defect in the predetermined region based on the density distribution of the magnetic dipoles, characterized in that the magnetization direction computer is configured to integrate a magnetic field distribution in a normal direction of the predetermined region among magnetic field distributions measured by the magnetic sensor array on a straight line in each of perpendicular directions with respect to the normal direction, and computes the magnetization direction based on integrated values obtained from integration on the straight line. a magnetization direction computer configured to compute a magnetization direction in the predetermined region of the metallic equipment based on the magnetic field distribution measured by the magnetic sensor array; a magnetic dipole density distribution calculator configured to calculate a density distribution of magnetic dipoles in the predetermined region based on the magnetic field distribution measured by the magnetic sensor array and the magnetization direction computed by the magnetization direction computer; and a depth distribution calculator configured to calculate a depth distribution of material defect in the predetermined region based on the density distribution of the magnetic dipoles, characterized in that the magnetization direction computer is configured to integrate a magnetic field distribution in a normal direction of the predetermined region among magnetic field distributions measured by the magnetic sensor array on a straight line in each of perpendicular directions with respect to the normal direction, and computes the magnetization direction based on integrated values obtained from integration on the straight line.