We have developed a noncontact temperature sensor using a silver halide optical fiber. The infrared collimator and focus head are connected both ends of a silver halide optical fiber with SMA connectors and used to collimate radiations of a heat source and to focus them to infrared sensors such as a pyroelectric sensor and a thermopile sensor, respectively. The relation ships between the temperatures of a heat source and the output signals of the infrared sensors are determined to measure the surface temperature of a heat source. The measurable temperature range is from 25 to $60^{circ}C$. It is expected that a noncontact temperature sensor using a silver halide optical fiber can be developed for medical usages such as temperature monitoring during hyperthermia, cryosurgery, laser surgery and diagnostic procedure based on the results of this study.