A production system for a product selected from a nitrogen-containing product and a fermented and cultured product that does not involve (or can minimize) the transport of liquid ammonia can include: an ammonia synthesis apparatus in which an ammonia-containing gas is synthesized by reaction of a source gas containing hydrogen and nitrogen in the presence of a supported metal catalyst containing as a support one or more selected from the group consisting of: i) a conductive mayenite compound; ii) a two-dimensional electride compound or a precursor thereof; and iii) a complex formed of a support base containing at least one metal oxide selected from ZrO2, TiO2, CeO2, and MgO and a metal amide represented by a formula M(NH2)x (where M represents one or more selected from Li, Na, K, Be, Mg, Ca, Sr, Ba, and Eu; and x represents a valence number of M) supported by the support base.