A microchip is provided, the microchip comprises a block constituting a reaction system, wherein said reaction system includes: a reaction region including biomolecules immobilized therein in form of a spot(s) or a strip(s); a supply flow channel connected to the reaction region for supplying a sample solution; and a recovery flow channel connected to the reaction region for recovering the sample solution which passes through at least a part of the reaction region. Thereby bonds or bindings between the biomolecules or biomacromolecules and the samples can be detected on the microchip using the slight quantity of both the sample and the biomolecules.