Disclosed are an auxiliary tray information detecting apparatus in which an RFID tag (110) is attached to the auxiliary tray (100) employed in the STS compounding the prescription with halves of tablets and/or special medicines not contained in a cassette and auxiliary tray information is automatically detected without contact, and a method thereof. The apparatus includes an RFID tag (110) in which medicine information and patient information are recorded； an RFID information reader (200) to read the information recorded in the RFID tag without contact； a PC (300) to compare the information with prescription information, to determine the auxiliary tray (100) as a predetermined auxiliary tray (100) when the information is identical to the prescription information, and to generate an alarm preventing a prescription error when the information is different from the prescription information； and an alarm device (400) to generate the alarm. The precise auxiliary tray information can be rapidly and conveniently detected without contact.
