Biological substance detecting apparatus

A biological substance detecting apparatus that employs a sensor chip provided with a fine flow channel through which a sample liquid is caused to flow, a portion of the interior of the fine flow channel being a sensor surface, on which a substance that specifically bonds with one of a detection target substance included in the sample liquid and a competing substance that competes against the detection target substance within the sample liquid is immobilized, comprising:

• light irradiating means, for irradiating light onto the sensor surface;
• light detecting means, for detecting light emitted by one of the detection target substance bound to the substance immobilized on the sensor surface, the competing substance bound to the substance immobilized on the sensor surface, a labeling substance bound to the detection target substance, and a labeling substance bound to the competing substance;
• and
• flow speed controlling means, for controlling the flow speed of the sample liquid that flows through the fine flow channel to a value within a range such that the speed of binding reactions between one of the detection target substance and the competing substance and the substance immobilized on the sensor surface is not controlled by dispersion.