A novel microfluidic device incorporating a two-dimensional array of microbeads with 10 mu m diameter was fabricated. Surface-modified microbeads to be used as detectors were arranged into microstructures prepared at the surface of a silica glass plate by laser-micromachining and sealed with a polydimethylsiloxane (PDMS) plate to form microchannels. The capturing reaction of surface amino groups with fluorescein isothiocyanate (FITC) supplied via microchannels was examined.