An action design apparatus comprising: a plurality of design units to generate design information in which a coordinated action among a plurality of devices is specified according to a user operation, each of the plurality of design units generating the design information in a different format; a design information conversion unit provided corresponding to each of the plurality of design units to convert the design information generated by the corresponding design unit into common design information described by using vocabulary stored in a dictionary unit as well as convert common design information generated from the design information generated by another design unit into design information in a format generated by the corresponding design unit; an output information conversion unit to convert output information output according to an action of each of the plurality of devices, into common output information described according to a common format provided for communication by using the vocabulary stored in the dictionary unit; an action definition generation unit to generate action definition information that specifies an action timing and action details of the plurality of devices in the coordinated action based on the common design information; and an action execution unit to act each device in a coordinated manner according to the common design information converted by the design information conversion unit as well as act each design unit according to the action definition information generated by the action definition generation unit and the common output information converted by the output information conversion unit. a plurality of design units to generate design information in which a coordinated action among a plurality of devices is specified according to a user operation, each of the plurality of design units generating the design information in a different format; a design information conversion unit provided corresponding to each of the plurality of design units to convert the design information generated by the corresponding design unit into common design information described by using vocabulary stored in a dictionary unit as well as convert common design information generated from the design information generated by another design unit into design information in a format generated by the corresponding design unit; an output information conversion unit to convert output information output according to an action of each of the plurality of devices, into common output information described according to a common format provided for communication by using the vocabulary stored in the dictionary unit; an action definition generation unit to generate action definition information that specifies an action timing and action details of the plurality of devices in the coordinated action based on the common design information; and an action execution unit to act each device in a coordinated manner according to the common design information converted by the design information conversion unit as well as act each design unit according to the action definition information generated by the action definition generation unit and the common output information converted by the output information conversion unit.