Abstract: This invention provides a method to monitor a microorganism that causes infectious disease of a laboratory animal by using a micro flow channel chip immobilized with a molecular to be tested such as an antigen or an antibody of the microorganism that causes infectious disease, the method comprises flowing serum or body fluid taken from the laboratory animal through the minute flow channel of the micro flow channel chip and detecting the antigen antibody reaction on the chip. The method of this invention enabled medical inspection of an infectious disease of a laboratory animal and microorganism monitoring of a laboratory animal, by using minute amount of animal serum or body fluid in a closed system rapidly and sensitively.