The present invention provides a flowrate control three-way valve and a temperature control device in which the operation failure of a driving means with respect to a fluid at a low temperature of approximately -85°C is further suppressed in comparison to the case where a drive-force transmission means and a joining means do not constitute a heat-transfer suppression part that is formed from a material having less heat conductivity than a valve body and a valve element and that suppresses the transmission of heat to the driving means.　The drive-force transmission means and the joining means are configured so as to constitute a heat-transfer suppression part that is formed from a material, such as zirconia, having less heat conductivity than a valve body and a valve element and that suppresses the transmission of heat to a driving means.