Microchannel device

A microchannel device of a microreactor unit comprising:

• a plurality of micro channels that includes a first channel and a second channel;
• and
• a merging channel that is formed at a downstream side of the plurality of micro channels, wherein
• the first channel branches into a plurality of first branch channels with a first branch structure,
• the first branch channels each branch into a plurality of second branch channels with a second branch structure,
• the first branch structure and the second branch structure being similar,
• the second channel and the plurality of second branch channels are connected to the merging channel at the downstream side,
• the second channel and the plurality of second branch channels are not connected to each other, other than the merging channel,
• a diameter of the first channel is larger than a diameter of each of the plurality of first branch channels,
• the diameter of each of the plurality of first branch channels is larger than a diameter of each of the plurality of second branch channels,
• a diameter of the second channel is substantially constant,
• the second channel extends alongside the first channel, the plurality of first branch channels, and the plurality of second branch channels from an input end of the first channel to output ends of the plurality of second branch channels,
• the first and second channels each have a plurality of segments including an upstream segment and a downstream segment, and
• the upstream segment of each of the plurality of segments has a cross-sectional shape that is different than the downstream segment of each of the plurality of segments.