Heating resistor type flow-measuring device comprising a bridge circuit which comprises - a heating resistor for generating heat by a current flowing through the heating resistor and a reference resistance which are connected in series and form a series connection circuit (2, 3) - serially-connected resistors (6, 11) which are connected to the series connection circuit (1, 2) in parallel, the serially-connected resistors (6, 11) comprising resistor means (7, 8, 9, 10) for adjusting the resistance ratio thereof and the heating temperature of the heating resistor through switching means (12, 13, 14, 15, 16), - said switching means, - comparing means (17; 78) connected to the junction between the heating resistor and the reference resistance (first potential) and to the junction between the serially-connected resistors (6, 11) (second potential) for determining the error voltage of the bridge circuit, and - driving means (5; 79) for controlling the current flowing through the heating resistor and for making the error voltage of the bridge circuit zero, characterized in that - the reference resistance is a thermoresistance capable of measuring the ambient temperature and is arranged on a planar substrate, - the heating resistor is arranged on a diaphragm formed in the planar substrate, - the resistor means (7, 8, 9, 10) are resistors (7, 8, 9, 10) connected in series between the serially-connected resistors (6, 11), thus forming a group of serially-connected resistors, - the switching means (12, 13, 14, 15, 16) are MOS transistors, wherein a switching input terminal of a first switching means is connected to the junction point of a first resistor and a second resistor among said serially-connected resistors (6, 7, 8, 9, 10, 11), a switching input terminal of a second switching means is connected to the junction point of the second resistor and a third resistor among said serially-connected resistors (6, 7, 8, 9, 10, 11), a switching input terminal of a third switching means is connected to the junction point of the third resistor and a fourth resistor among said serially-connected resistors (6, 7, 8, 9, 10, 11), a switching input terminal of a fourth switching means is connected to the junction point of the fourth resistor and a fifth resistor among said serially-connected resistors (6, 7, 8, 9, 10, 11), and a switching input terminal of a fifth switching means is connected to the junction point of the fifth resistor and a sixth resistor among said serially-connected resistors (6, 7, 8, 9, 10, 11), and a switching output terminal of each of the switching means (12, 13, 14, 15, 16) (second potential) being connected to the comparing means (17; 78). - a heating resistor for generating heat by a current flowing through the heating resistor and a reference resistance which are connected in series and form a series connection circuit (2, 3) - serially-connected resistors (6, 11) which are connected to the series connection circuit (1, 2) in parallel, the serially-connected resistors (6, 11) comprising resistor means (7, 8, 9, 10) for adjusting the resistance ratio thereof and the heating temperature of the heating resistor through switching means (12, 13, 14, 15, 16), - said switching means, - comparing means (17; 78) connected to the junction between the heating resistor and the reference resistance (first potential) and to the junction between the serially-connected resistors (6, 11) (second potential) for determining the error voltage of the bridge circuit, and - driving means (5; 79) for controlling the current flowing through the heating resistor and for making the error voltage of the bridge circuit zero, - the reference resistance is a thermoresistance capable of measuring the ambient temperature and is arranged on a planar substrate, - the heating resistor is arranged on a diaphragm formed in the planar substrate, - the resistor means (7, 8, 9, 10) are resistors (7, 8, 9, 10) connected in series between the serially-connected resistors (6, 11), thus forming a group of serially-connected resistors, - the switching means (12, 13, 14, 15, 16) are MOS transistors,