An action control device that controls an action of a control target device, the action control device comprising: a controller that acquires an external stimulus applied to the control target device, and calculates a characteristic parameter of the acquired external stimulus, characterized in that the controller stores the calculated characteristic parameter in a storage as a stored parameter without associating with a subject applying the external stimulus, calculates, for each stored parameter, a similarity between a plurality of the stored parameters previously stored and the calculated characteristic parameter that is a latest characteristic parameter, counts, as a counter variable for counting, a number of stored parameters, among the plurality of stored parameters, of which corresponding similarities are equal to or greater than a predetermined threshold, determines, based on the counted counter variable, an intimacy between the subject applying the external stimulus and the control target device, and sets an action amount of time of an intimate action mode of the control target device in accordance with the determined intimacy to cause the control target device to execute different action content based on the determined intimacy. a controller that acquires an external stimulus applied to the control target device, and calculates a characteristic parameter of the acquired external stimulus, characterized in that the controller stores the calculated characteristic parameter in a storage as a stored parameter without associating with a subject applying the external stimulus, calculates, for each stored parameter, a similarity between a plurality of the stored parameters previously stored and the calculated characteristic parameter that is a latest characteristic parameter, counts, as a counter variable for counting, a number of stored parameters, among the plurality of stored parameters, of which corresponding similarities are equal to or greater than a predetermined threshold, determines, based on the counted counter variable, an intimacy between the subject applying the external stimulus and the control target device, and sets an action amount of time of an intimate action mode of the control target device in accordance with the determined intimacy to cause the control target device to execute different action content based on the determined intimacy. stores the calculated characteristic parameter in a storage as a stored parameter without associating with a subject applying the external stimulus, calculates, for each stored parameter, a similarity between a plurality of the stored parameters previously stored and the calculated characteristic parameter that is a latest characteristic parameter, counts, as a counter variable for counting, a number of stored parameters, among the plurality of stored parameters, of which corresponding similarities are equal to or greater than a predetermined threshold, determines, based on the counted counter variable, an intimacy between the subject applying the external stimulus and the control target device, and sets an action amount of time of an intimate action mode of the control target device in accordance with the determined intimacy to cause the control target device to execute different action content based on the determined intimacy.