The pass box is a kind of auxiliary equipment of the clean room. It is mainly used for the transfer of small items between the clean area and the clean area, between the clean area and the non-clean area, so as to reduce the number of door openings in the clean room and reduce the pollution to a minimum. The pass box is made of stainless steel plate, smooth and clean. The double doors are interlocked to effectively prevent cross-contamination, equipped with electronic or mechanical interlocking devices, and equipped with ultraviolet germicidal lamps.