To provide a planar magnetometric sensor of high sensitivity which is thinned and measures magnetic fields for a plenty of measuring points in a very short period of time.

The magnetometric sensor comprises: at least one sensing layer 11 formed in a sheetlike magnetoresistive effect membrane; conductive layers 12, 13 formed with a plurality of linear conductive membranes formed in narrow linear shape and placed with a prescribed intervals on each surface of the magnetoresistive membrane; and insulation layers 41, 42 laminated on both the sides of the sensing layer 11.