The present invention relates to a device which is to be utilized at the time of observation of a mixed state or a chemically-combined state of a mixture attained by mixing together trace amounts of gases or trace amounts of liquids or mixing a trace amount of a gas with a trace amount of liquid. A micropump 1 comprises a pump structural material having a reaction chamber formed therein; a reaction agent 4 which is housed in a reaction chamber 6 and produces a gas of predetermined pressure; reaction initiation means 5 which is disposed beside the reaction agent and causes the reaction agent to produce a gas; and a channel 7 which is provided in the pump structural material and guides the gas of predetermined pressure produced by the reaction agent from the reaction chamber to an outlet port. The pump structural material and the reaction initiation means are stacked one on top of the other.