Provided is a fuel cell module and a fuel cell device of which power generation efficiency is improved.A fuel cell device includes a fuel cell module including a housing and a fuel cell stack which is composed of a plurality of fuel cells and is inside the housing, a power conditioner configured to supply electric current generated by the fuel cell stack to an external load, and a controller configured to control the power conditioner such that, at a time of starting power generation, a voltage value of the fuel cells is greater than a voltage value for generating a maximum output in power generation of the fuel cells, and the fuel cell module, the power conditioner and the controller are accommodated in an external case. Accordingly, deterioration of the fuel cells can be suppressed, and the fuel cell device having improved reliability can be obtained.