A thermal flow rate sensor that is provided with a plurality of electrode pads for electrical conduction with an outside and includes a semiconductor element that detects a flow rate, wherein an electrode pad that is adjacent to an electrode pad through which a flow rate signal is output of the plurality of electrode pads is an electrode pad that has an electrical potential outside of an output range used at a time of a flow rate detection, characterized in that: the semiconductor element is provided with at least one or more heat resistors, the upstream side and downstream side of which are both provided with a temperature measuring resistor (22, 23) for detecting a temperature difference between the upstream and downstream temperature measuring resistors, a semiconductor power supply element that drives the heat resistor is electrically connected to the one or more heat resistors, and a flow rate is detected based on the temperature difference between the upstream and downstream temperature measuring resistors, the semiconductor element includes a circuit in which a voltage value that is output due to the temperature difference between the upstream and downstream temperature measuring resistors is converted to a digital value by an analog/digital converter circuit, and wherein a voltage range of the analog/digital converter circuit is defined as -VD to +VD, an electrical potential of the upstream midpoint of the bridge circuit is defined as OUT1, an electrical potential of the downstream midpoint of the bridge circuit is defined as OUT2, and an electrical potential of a pad, being provided between electrode pads (S1, S2) of the upstream and downstream midpoints of the circuit and said pad supplying power to the temperature measuring resistors for the flow rate signal is OUT3, wherein |OUT3 - OUT1| > |VD| and |OUT3 - OUT2| > |VD| are always true regardless of a presence of air flow and environment temperature change. the semiconductor element is provided with at least one or more heat resistors, the upstream side and downstream side of which are both provided with a temperature measuring resistor (22, 23) for detecting a temperature difference between the upstream and downstream temperature measuring resistors, a semiconductor power supply element that drives the heat resistor is electrically connected to the one or more heat resistors, and a flow rate is detected based on the temperature difference between the upstream and downstream temperature measuring resistors, the semiconductor element includes a circuit in which a voltage value that is output due to the temperature difference between the upstream and downstream temperature measuring resistors is converted to a digital value by an analog/digital converter circuit, and wherein a voltage range of the analog/digital converter circuit is defined as -VD to +VD, an electrical potential of the upstream midpoint of the bridge circuit is defined as OUT1, an electrical potential of the downstream midpoint of the bridge circuit is defined as OUT2, and an electrical potential of a pad, being provided between electrode pads (S1, S2) of the upstream and downstream midpoints of the circuit and said pad supplying power to the temperature measuring resistors for the flow rate signal is OUT3, wherein |OUT3 - OUT1| > |VD| and |OUT3 - OUT2| > |VD| are always true regardless of a presence of air flow and environment temperature change.