A peripheral device (10, 60), connectable to an upper apparatus (30, 80) and a dependent peripheral (20, 70) based on USB, comprising: a USB control unit (113, 603) that executes a device definition with respect to the upper apparatus (30, 80) according to a selection instruction of an operator in order to allow the upper apparatus (30, 80) to specify either the peripheral device (10, 60) or the dependent peripheral (20,70) as a communication partner destination, wherein said USB control unit (113, 603) has a host control section (1132, 6032) that executes USB communication between the peripheral device (10, 60) and the dependent peripheral (20, 70) in accordance with a USB protocol, characterized in that said USB control unit (113, 603) has a data transmitting and receiving section (1131, 6031) used for transmitting and receiving data with the upper apparatus (30, 80), and said host control section (1132, 6032) is used for transmitting and receiving data with the dependent peripheral (20, 70), wherein in the case that the peripheral device (10, 60) is specified as the communication partner destination with respect to the upper apparatus (30, 80), the data transmitting and receiving section (1131, 6031) is adapted to receive data from and transmit data to the upper apparatus (30, 80); and in the case that the dependent peripheral (20, 70) is specified as the communication partner destination with respect to the upper apparatus (30, 80), the data transmitting and receiving section (1131, 6031) is adapted to receive data from the upper apparatus (30, 80), the peripheral device (10, 60) is adapted to transfer the data from the data transmitting and receiving section (1131, 6031) to the host control section (1132, 6032), and the host control section (1132, 6032) is adapted to transmit the data to the dependent peripheral (20, 70) by control of the upper apparatus (30, 80), and vice versa. a USB control unit (113, 603) that executes a device definition with respect to the upper apparatus (30, 80) according to a selection instruction of an operator in order to allow the upper apparatus (30, 80) to specify either the peripheral device (10, 60) or the dependent peripheral (20,70) as a communication partner destination, wherein said USB control unit (113, 603) has a host control section (1132, 6032) that executes USB communication between the peripheral device (10, 60) and the dependent peripheral (20, 70) in accordance with a USB protocol, characterized in that said USB control unit (113, 603) has a data transmitting and receiving section (1131, 6031) used for transmitting and receiving data with the upper apparatus (30, 80), and said host control section (1132, 6032) is used for transmitting and receiving data with the dependent peripheral (20, 70), wherein in the case that the peripheral device (10, 60) is specified as the communication partner destination with respect to the upper apparatus (30, 80), the data transmitting and receiving section (1131, 6031) is adapted to receive data from and transmit data to the upper apparatus (30, 80); and in the case that the dependent peripheral (20, 70) is specified as the communication partner destination with respect to the upper apparatus (30, 80), the data transmitting and receiving section (1131, 6031) is adapted to receive data from the upper apparatus (30, 80), the peripheral device (10, 60) is adapted to transfer the data from the data transmitting and receiving section (1131, 6031) to the host control section (1132, 6032), and the host control section (1132, 6032) is adapted to transmit the data to the dependent peripheral (20, 70) by control of the upper apparatus (30, 80), and vice versa.