A new instrument was developed for measuring the local moisture content in moist porous media based on the needle-type capacitance sensor and single-chip microprocessor technique. The working principle, the structure and characteristics of the hardware and software of the instrument were presented. The dynamic response characteristics and reliability of the instrument were experimentally determined. As an example, the instrument was employed to measure the heat and mass transport properties of a moist porous material. The experimental results show that the instrument can be used for measuring the local moisture content in moist porous media and would be an effective tool for determining the heat and mass transport properties in moist porous media.