An egg search code, that can be used for accurately searching history information of an egg using a number of digits printable on the egg, is assigned to the egg, and the history information of the egg can be accurately identified based on the egg search code assigned to the egg. An unused egg search code out of the totality of egg search codes is determined and will be used as the egg search code to be assigned to the egg. The determined egg search code is assigned to all eggs having identical history information. The egg search code assigned to the egg is related to the egg history code and an egg collection date code, and is stored. The egg history code related to the egg collection date code and the egg search code is searched for, in compliance with a provision request, submitted from a consumer terminal, for history information, the provision request containing the egg collection date code and/or the egg search code. The history information identified by the searched egg history code is transmitted to the consumer terminal through a communication network.