An apparatus for evaluating scientific phenomena by feeding liquid to a minute channel, which is inexpensive, imposes little environmental load and enables advanced technology to be easily enjoyed and can eliminate experimental failures due to the clogging of the minute channel with a bubble, is provided. Before starting the experiment with the experimental liquid, the preparatory step of removing air in the minute channel by vigorously injecting inert dummy liquid which does not react with the experimental liquid into the minute channel and thereby filling the minute channel with the dummy liquid is carried out. If one round of preparatory step proves insufficient to wholly remove the air in the minute channel and a bubble is found in the dummy liquid, the step will be repeated until no bubble is found any longer in the dummy liquid. Next, the experiment is started by supplying the experimental liquid to inlet side liquid reservoirs and causing liquid feeding device to let the dummy liquid filling the minute channel flow to outlet side liquid reservoirs.