A microchip 100 is employed as target board of mass spectrometry. The microchip 100 includes a substrate 120, a plurality of sample-distributing sections, provided in the substrate 120 and contains samples that serve as a target of a mass spectrometry distributed therein, and a reference material-supplying channel provided in the substrate 120 and capable of being supplied with a reference material in the mass spectrometry. The plurality of sample-distributing sections are provided in the lateral side of the fine channel 102 for distributing the reference material along the fine channel 102 for distributing the reference material.