In response to food contamination by radioactive materials arising from the Fukushima Daiichi Nuclear Power Station Accident, new standard limits for radioactive materials in food were established in 2012 in Japan. As it is possible that infants have a higher sensitivity to radiation than adults, the standard limit for infant food (50 Bq/kg) was set at half the limit for food in general (100 Bq/kg). As infant foods are not as rigorously monitored by municipalities as fresh foods, it is crucial that infants’ exposure to radiation be assessed by measuring and understanding the concentration of radioactive materials in infant foods. In this study, we investigated the concentration of radioactive cesium (Cs-134 and Cs-137) in 906 samples of infant foods available on the Japanese market from 2012 to 2023 using a germanium semiconductor detector. The sum of the limit of detection for Cs-134 and Cs-137 was set as less than 5 Bq/kg for infant foods and less than 1 Bq/kg for drinking water for infants. Totals of 238 samples of infant formula, 471 samples of infant foods, and 197 samples of snacks and beverages were analyzed, with none of the samples exceeding the new standard limits and the limit of detections for radioactive cesium. These results suggest that manufacturers have implemented strict production management procedures since the accident so that the intake of radioactive cesium from infant foods produced in Japan is negligibly low.