are fixed onto the inner wall bottom side in the figure of the cartridge 11 when a voltage is supplied by the voltage source 14 to the electrodes 12 and 13 an unknown dna in suspension is attracted toward the positive electrode 12 as shown in fig3 b since the unknown dna segment is negatively charged thus the unknown dna segment approaches toward a known dna segment as a result the speed of hybridization is increased by reversing the electrode polarity after hybridization it is possible to separate wrongly hybridized dna segment pairs consequently it is possible to precisely measure even a one base difference as seen in snps it is possible to label dna segments with a fluorescent reagent and observe the segments in the same way as practiced in the prior art preferably the electrodes 12 and 13 are configured so that the electrodes can be removed from the cartridge 11 after hybridization removing the electrodes 12 and 13 from the cartridge 11 after hybridization will make it easy to observe the cartridge 11 through an objective lens 21 as shown in fig4 it should be noted that the present invention is by no means limited to the above described embodiment the invention may be embodied in other ways without departing from the spirit and essential characteristics thereof accordingly it should be understood that all modifications falling within the spirit and scope of the present invention are covered by the appended claims for example the positive electrode 12 may be alternatively configured in such a manner that a.