To provide a micro process method which is suitable for an application to a process system containing a process carried out at a temperature of the boiling point or more of a fluid component contained in a fluid.

The micro process method comprises the processes of supplying a raw fluid in the micro process system containing a micro fluid device 2 having a microchannel 21 where the process is carried out, and a transport channel 25 communicating with the microchannel 21, and at the same time, of transporting the process fluid flown out from the microchannel 21 via the process, through the transport channel 25. The raw fluid is supplied into the micro process system under pressure of a steam pressure or more of the lowest boiling point fluid component contained in the raw fluid and the process fluid, and at the same time, the process fluid is transported to the outside of the microchannel 21.