To provide an apparatus which evaluates a scientific phenomenon by feeding a liquid to minute channels, is inexpensive, is small in environmental load, and enables a user to enjoy advanced technology, and to avoid experimental failure due to air bubble clogging inside minute channels.

A preparatory step of removing air from the inside of the minute channels 14A, 16A and 20A in advance is performed by causing an inactive dummy liquid 35 which does not react with an experimental liquid 34 for performing an experiment to flow vigorously into and fill the minute channels 14A, 16A and 20A before the commencement of an experiment with the experimental liquid 34. When the air inside the minute channels is not completely removed by the preparatory step of one time and the air bubbles of the dummy liquid are seen, the preparatory step is repeated until the air bubbles do not exist any more in the dummy liquid. Next, the experimental liquid 34 is supplied to the reservoirs 24 and 26 on the inlet side and the dummy liquid 35 filling the minute channels 14A and 16A and 20A is caused to flow toward the reservoir 28 on the outlet side by a liquid feed means, by which the experiment is started.