A heat flow distribution measurement device includes a sensor module having one multilayer substrate and a plurality of heat flow sensor portions arranged inside of the multilayer substrate. The multilayer substrate has one surface and another surface opposite to the one surface and includes a plurality of stacked insulating layers each formed of a thermoplastic resin. The heat flow sensor portions are each formed of thermoelectric conversion elements and are thermoelectrically independent. An arithmetic portion arithmetically determines a heat flow distribution based on an electromotive force generated in each of the heat flow sensor portions. The thermoelectric conversion elements are formed in the multilayer substrate and therefore manufactured by the same manufacturing process for manufacturing the multilayer substrate. This can minimize the performance difference between the individual thermoelectric conversion elements and allow the heat flow distribution to be measured with high precision.