A monitoring apparatus communicatively coupled to one or more devices forming an information processing system manages each of the devices by setting the device to be in any one of monitoring states including a monitoring target to be always monitored, a semi-monitoring target to be determined if there is a change in resources and a non-monitoring target being neither the monitoring target nor the semi-monitoring target. The monitoring apparatus newly acquires resource information on a device whose monitoring state is currently set to be the monitoring target or the semi-monitoring target, and determines if any of the resources of the device is changed on the basis of the newly acquired resource information, the resource information acquired last time, and a determination condition. When determining that any of the resources has been changed, the monitoring apparatus outputs a screen prompting a change of the monitoring state of the device.