A micro fluid device includes a heating unit and a cooling unit, each with piping disposed within. The heating and cooling units are integrally coupled together, and fluid flows into the piping of respective units. A temperature control device includes a heat insulator which has a through hole equal in diameter to the piping disposed within the heating unit and cooling unit. The heat insulator is interposed between heating unit and the cooling unit. A positioning mechanism positions the heat insulator to bring the piping into communication with the through hole at the time of coupling the heating and cooling units.