The paper presents the constant temperature digital hot-film anemometer that measures easily a wind velocity at the indoor. The output is linearized using microprocessor and analog-to-digital converter, because the fourth root of the wind velocity is the output voltage of the sensor. The comparison result between fabricated and reference anemometer is less than ${pm}2%$. In the range of air temperature of $23^{circ}C{sim}60^{circ}C$, the error is about ${pm}1%$ in wind velocity 10m/sec.