Method for producing microchannel device

A method for producing a microchannel device that has a channel sandwiched between channel walls formed in an inside of a porous substrate, comprising:

• placing a first hydrophobic resin on a surface of the porous substrate to form a channel pattern on the surface of the porous substrate;
• and
• melting the first hydrophobic resin by heat to allow the first hydrophobic resin to permeate into the inside of the porous substrate, thereby forming the channel wall in the inside of the porous substrate, wherein
• when the channel wall is formed, the first hydrophobic resin is allowed to permeate at a temperature at which a storage elastic modulus G′ of the first hydrophobic resin is 14 Pa or lower, and a loss elastic modulus G″ thereof is 10 Pa or higher.