An information collecting system collects information associated with (i) a controller connected to a control network and (ii) a host device connected to an information network located at a level higher than the control network, and includes a management device and an information collecting mediation device. The management device is connected to the information network, collects information associated with the host device, transmits an acquisition request for information associated with the controller to the information network, and manages the collected information associated with the host device and information associated with the controller. The information collecting mediation device is connected to the control network and the information network, collects information associated with the controller according to capability information indicating a capability of at least one of the control network and the controller based on the acquisition request, and sends said collected information to the management device.