1. An email processing apparatus comprising: a category determining unit configured to determine a content category of an email, from at least one of a main body of the email and a subject of the email stored in an email storage unit; a specifying unit configured to specify a search target category to which the search target email relating to the email belongs, based on the content category determined by the category determining unit; a acquiring unit configured to acquire search target information for searching for the search target email belonging to the search target category; and a creating unit configured to create a search condition for searching for the search target email that contains the search target information and belongs to the search target category, from the email storage unit.