In the searchable encryption processing system, a data base server retaining data, a registration client which deposits the data into the data base server, and a search client which causes the data base server to search the data collaborate across a network, wherein the registration client, using a probabilistic encryption method which uses a mask using a homomorphic function and a hash value, deposits the encrypted data into the server, whereupon the search client, using probabilistic encryption which uses the mask which uses the homomorphic function for encryption of the search query, outputs the search query and non-corresponding data as search results without causing the data base server to unmask the mask and without allowing the frequency of occurrences of the data corresponding to the search to leak to the data base server.