There is provided a biochip capable of quantitatively grasping hybridization efficiency. In the biochip comprising a plurality of probe sites with target molecules bonded thereto, respectively, the probe sites disposed thereon, the marker sites with a known number of fluorescent molecules bonded thereto, respectively, are disposed. With the biochip, the number of the fluorescent molecules bonded to the respective marker sites is already known, so that respective hybridization efficiencies at the probe sites can be quantitatively grasped by comparing respective intensity of fluorescent light of the probe sites with an intensity of fluorescent light of the marker sites. The fluorescent molecule may be bonded to the respective marker sites when the biochip is formed, or the respective marker sites may be made up such that the fluorescent molecule of a predetermined molecular weight is bonded thereto by a predetermined processing applied to the biochip. The respective marker sites may be formed by use of a biopolymer of the same species as that for the respective probe sites.
Method for analyzing a biochip