In many applications a reader needs to determine whether a particular tag exists within a group of tags without a server. This is referred to as serverless RFID tag searching. A few protocols for the serverless RFID searching are proposed but they are the single tag search protocol which can search a tag at one time. In this paper, we propose a multi-tag search protocol based on a hash function and a random number generator which can search some tags at one time. For this study, we introduce a protocol which can resolve the problem of synchronization of seeds when communication error occurs in the S3PR protocol[1], and propose a multi-tag search protocol which can reduce the communication overhead. The proposed protocol is secure against tracking attack, impersonation attack, replay attack and denial-of-service attack. This study will be the basis of research for multi-tag serach protocol.