The probe measuring the thermal conductivity of food materials under pressurized conditions over a wide temperature range was developed. The measurement was based on the transient hot wire method. The validity of the data measured using this probe was verified by comparison with published data of water. The thermal conductivity of gelatinized potato starches was determined at 25-80 °C, 50-80% moisture, and 0.2-10 MPa. It was found that the thermal conductivity of the starch gel increases with temperature and moisture content, and that it increases with pressure up to 1 MPa, above which it remains almost constant.