To provide a minute chemical device in which dissolved air of a solution is not deposited in the reaction part and a channel in the analysis part, and the evaporation of a solvent from a reaction solution is controlled when the device is used for analysis and a reaction and which is excellent in reproducibility.

In the device having a heating/deairing mechanism and a capillary channel having a hydrophilic surface, the channel passes through a heating/ deairing part to be heated at 60-115°C which is formed in a part of the device, and a vent passage having a hydrophobic surface is divided from the channel in the heating/deairing part.