A network system comprising at least one equipment (6; 103), a client terminal device, and a server connected between said equipment (6; 103) and said client terminal device via a network, and configured such that said client terminal device requests an execution of a server-side object to said server, and then said server requests an execution of an equipment-side object to said equipment (6; 103), the execution request of said server-side object from said client terminal device is performed by use of a first identifier assigned to said server-side object, and the execution request of said equipment-side object from said server is performed by use of a second identifier assigned to said equipment-side object, said second identifier comprises at least one identifier defined according to a function of said equipment (6; 103), which executes said equipment-side object according to the execution request of said server-side object using said first identifier from said client terminal device, said equipment (6; 103) comprises a function portion (60; 130) configured to execute processing for providing a service of said equipment (6; 103), and an information processing portion (63; 133) having said equipment-side object, which is used when said function portion (60; 130) executes processing for providing the service, said information processing portion (63; 133) is configured to, when the information processing portion (63; 133) receives said execution request of said equipment-side object using said second identifier, execute said equipment-side object corresponding to said second identifier, and give to and receive from said function portion (60; 130) information defined in said equipment-side object and needed to provide the service, said server has a service provision function portion, a service request function portion, and an identifier setting portion configured to set a correspondence relation between said first identifier and said second identifier, said service provision function portion has said server-side object and is configured to, upon receiving the execution request of said server-side object using said first identifier from said client terminal device, execute said server-side object corresponding to said first identifier, said service request function portion is configured to, when said server-side object is executed, send, to said equipment (6; 103) via the network, the execution request of said equipment-side object using said second identifier corresponding to said first identifier with reference to said correspondence relation set by said identifier setting portion, in order to give to and receive from said equipment information corresponding to the service, said service provision function portion has a definition needed to convert information corresponding to the service into the provision service for client, said service provision function portion is configured to convert said information corresponding to the service where said service request function portion acquired from said equipment into the provision service for client based on said definition, and said client terminal device is configured to receive from said service provision function portion said provision service for client.