To prevent influence accompanying the law revision of a medical work accounting system by referring to a conversion master by received data, and when data matched with respective inspection items for respective inspection materials on a medical side are present, converting them into the corresponding data composed of the respective inspection items for the respective inspection materials on a medical work accounting side and deciding agent constitution.

A preprocessing means 2 reads the received data grouped for the respective inspection materials and composed of the inspection items to which the inspection materials are added from the medical side from an accounting information file 5 and preprocesses them. The conversion master 6 is referred to for the preprocessed data, and when the data matched with the plural inspection items for the respective inspection materials on the medical side are present, a conversion means 3 converts them to the corresponding data composed of the plural inspection items for the respective inspection materials on the medical work accounting side. Then, based on the converted data, the agent constitution is decided by an agent decision means 4 and stored in an output file 8.