The aim of this study was to elucidate the mechanism of the tongue movement in an infant during sucking. Therefore, we constructed a system for measuring the force applied by an infant tongue to an artificial nipple using a point-contact force sensor. The force sensor consists of a pressure transducer and a stainless steel ball. Any force applied to the artificial nipple is transmitted to the pressure transducer, via point contact with the stainless steel ball. The sensors are arranged at the tip and base of the nipple to capture peristaltic-like movements of the tongue. This system is portable and resembles a feeding bottle. Since the sucking period, output signal, the order in which force is applied to the sensor, and the time difference are displayed on the integrated LCD screen, measurement results are available immediately. Using this system, we performed measurements on infants with different nutritional states. In infants capable of breastfeeding, sucking involves peristaltic-like movements of the tongue. In infants incapable of breastfeeding, the base and the tip of the tongue contact the nipple at the same time. In addition, pediatricians validated this system, demonstrating that adaptation to the clinic is possible.