A thermal flow rate sensor is provided which includes a main flow path through which a fluid flows, and a sensor flow path that branches off from the main flow path so as to cause the fluid to flow in a split flow and that is provided with a flow rate detecting mechanism configured to detect a flow rate of the fluid. The flow rate detecting mechanism includes an upstream-side coil and a downstream-side coil, each configured by using a heat-generating resistance wire wound around a sensor flow pipe forming the sensor flow path. A peak position of a temperature distribution generated in the sensor flow path by the upstream-side coil and the downstream-side coil is positioned on the upstream-side coil side relative to the middle position between the upstream-side coil and the downstream-side coil on the sensor flow path.