To provide a recommend device capable of outputting suitable recommend information on an intended purchase object base.

The recommend device is provided with a history information storing part 12 for storing history information showing the merchandise purchased by a user in the past, a calculating part 14 for calculating a value corresponding to a conditional probability that the user purchases each merchandise Pj by using a general expression while referring to the history information when the user purchases merchandise P1, ..., Pn with the past merchandise purchased by a certain user as P1, ..., Pn and with the other merchandise as Pj (j is n+1 or more), a selecting part 15 for selecting recommended merchandise by using the calculated value, and an outputting part 16 for outputting recommend information including the identification information of the selected merchandise.