Biomolecules are specifically captured with magnetic particles and the biomolecules are labeled with fluorescence. A magnetic field generator, for attracting the magnetic particles to the support substrate, is provided on the reverse face of the support substrate, and an adhesion layer is provided on the surface of the support substrate to hold the magnetic particles. First, a dispersing solution for the magnetic particles is placed on the surface of the support substrate with the magnetic field in an off state. Next, the magnetic field is turned on, and the magnetic particles in solution are attracted to the support substrate surface. The magnetic particles colliding with the support substrate adhere to the adhesion layer of the support substrate surface, and then the magnetic field is turned off. Thus, aggregations can be broken up while the magnetic particles are held, and a magnetic particle layer on the support substrate can be a single layer.