A heat quantity control device comprising: a heat flux sensor arranged between a first heating element and a second heating element which are arranged adjacently to each other; and a control section capable of controlling a heat quantity of at least one of the first heating element and the second heating element wherein the heat flux sensor comprises an insulation board made of a thermoplastic resin, a plurality of first via holes and second via holes are formed in the insulation board so that the first via holes and the second via holes pass through a thickness direction of the insulation board, first layer connection members and second layer connection members are embedded in the first via holes and the second via holes, respectively, the first layer connection members and the second layer connection members are made of different metals, and the first layer connection members and the second layer connection members are alternately connected in series, and in the heat flux sensor, a front surface protection member is formed on a surface of the insulation board, a front surface pattern is formed on the front surface protection member, and a back surface protection member is formed on a back surface of the insulation board, a back surface pattern is formed on the back surface protection member, and the back surface protection member, the insulation board and the front surface protection member are assembled together, the first layer connection members and the second layer connection members alternately connected to each other generate an electromotive force due to a heat flux flowing between the first heating element and the second heating element, and the control section controls a heat quantity generated in the first heating element and the second heating element on the basis of the electromotive force generated in the heat flux sensor so that the heat flux flowing between the first heating element and the second heating element becomes not more than a predetermined value. a heat flux sensor arranged between a first heating element and a second heating element which are arranged adjacently to each other; and a control section capable of controlling a heat quantity of at least one of the first heating element and the second heating element wherein the heat flux sensor comprises an insulation board made of a thermoplastic resin, a plurality of first via holes and second via holes are formed in the insulation board so that the first via holes and the second via holes pass through a thickness direction of the insulation board, first layer connection members and second layer connection members are embedded in the first via holes and the second via holes, respectively, the first layer connection members and the second layer connection members are made of different metals, and the first layer connection members and the second layer connection members are alternately connected in series, and in the heat flux sensor, a front surface protection member is formed on a surface of the insulation board, a front surface pattern is formed on the front surface protection member, and a back surface protection member is formed on a back surface of the insulation board, a back surface pattern is formed on the back surface protection member, and the back surface protection member, the insulation board and the front surface protection member are assembled together, the first layer connection members and the second layer connection members alternately connected to each other generate an electromotive force due to a heat flux flowing between the first heating element and the second heating element, and the control section controls a heat quantity generated in the first heating element and the second heating element on the basis of the electromotive force generated in the heat flux sensor so that the heat flux flowing between the first heating element and the second heating element becomes not more than a predetermined value.