Provided are a humidity sensor and a method of manufacturing the same. The humidity sensor has high sensitivity, quick response time, improved temperature characteristics, low hysteresis and excellent durability. Moreover, for the humidity sensor, a humidity sensitive layer may be formed of various materials. The humidity sensor may be manufactured in a small size on a large scale.The humidity sensor includes a substrate, an open cavity with an open upper portion formed to have a depth and a width in the substrate, a plurality of electrode pads formed on the substrate, a heater connected to one pad of the electrode pads at one end, and connected to another pad of the electrode pads at the other end to be suspended over the open cavity, a plurality of sensing electrodes formed on the same plane as the heater, and suspended over the open cavity to output a sensed signal to the electrode pads, a humidity sensitive layer formed on the heater and the sensing electrodes, suspended over the open cavity, and changed in characteristic according to the humidity, and an ambient temperature measurement part configured to measure the temperature around the humidity sensor, wherein the temperature is used as a reference temperature to control a heating temperature of the heater.