Injuries to preschool children when using carrying devices were analyzed by reviewing the Childhood Injury Surveillance Database developed by National Institute of Advanced Industrial Science and Technology in Japan. Injuries related to the four most popularly used baby carrying devices, were investigated. In addition to the analysis of routine factors identified in the injury database, an Objects in Injury Process Matrix (OIPM) was developed to understand the role of each object involved in these unintentional injuries. Each selected case was examined and statistical methods were used to examine the distributions and features of injuries. The Chi-squared test was used to determine the significance of differences between groups. SPSS statistical software (version 22.0) was used for the analysis. Significant differences were found between type of carrying device and child age, type of injury, treatment status, and time of injury. The major role of each object in the injury process was clarified by the OIPM method. Cases of injury to preschool children, related to four kinds of popular carrying device, were identified and extracted from the injury database. The characteristics and mechanism of injury were clarified. Using an original method developed, the OIPM, we combined routine data with information extracted from free text. When needed, we re-examined the original text to obtain more specific information about the injury event and related conditions. The OIPM enabled us to examine the data in a more systematic manner to reveal the potential mechanism of injury. The results showed each carrying device to have unique inherent risks.The findings of this study are helpful in reducing child-related injuries, promoting improved design of products for safety, and guiding governmental public safety policies.