A master device providing an image to a slave device providing a virtual reality service, comprising: a content input configured to receive an input image; a communicator; and a processor configured to: identify a viewpoint region in the input image on the basis of motion information received from the slave device and control the communicator to transmit an image of the identified viewpoint region to the slave device, characterized in that: the input image is a stereoscopic image; and the viewpoint region corresponds to a motion state of the corresponding slave device, the master device further comprises a sensor sensing a motion state of the master device, the processor obtains relative motion information corresponding to the slave device by calibrating the motion information received from the slave device based on the sensed motion state, and identifies the viewpoint region corresponding to the motion state of the slave device based on the obtained relative motion information, and the processor is further configured to obtain the viewpoint region in a left-eye stereoscopic space image and a right-eye stereoscopic space image obtained by projecting a left-eye image and a right-eye image included in the input stereoscopic image into a virtual stereoscopic space. a content input configured to receive an input image; a communicator; and a processor configured to: identify a viewpoint region in the input image on the basis of motion information received from the slave device and control the communicator to transmit an image of the identified viewpoint region to the slave device, characterized in that: the input image is a stereoscopic image; and the viewpoint region corresponds to a motion state of the corresponding slave device, the master device further comprises a sensor sensing a motion state of the master device, the processor obtains relative motion information corresponding to the slave device by calibrating the motion information received from the slave device based on the sensed motion state, and identifies the viewpoint region corresponding to the motion state of the slave device based on the obtained relative motion information, and the processor is further configured to obtain the viewpoint region in a left-eye stereoscopic space image and a right-eye stereoscopic space image obtained by projecting a left-eye image and a right-eye image included in the input stereoscopic image into a virtual stereoscopic space. identify a viewpoint region in the input image on the basis of motion information received from the slave device and control the communicator to transmit an image of the identified viewpoint region to the slave device, characterized in that: the input image is a stereoscopic image; and the viewpoint region corresponds to a motion state of the corresponding slave device, the master device further comprises a sensor sensing a motion state of the master device, the processor obtains relative motion information corresponding to the slave device by calibrating the motion information received from the slave device based on the sensed motion state, and identifies the viewpoint region corresponding to the motion state of the slave device based on the obtained relative motion information, and the processor is further configured to obtain the viewpoint region in a left-eye stereoscopic space image and a right-eye stereoscopic space image obtained by projecting a left-eye image and a right-eye image included in the input stereoscopic image into a virtual stereoscopic space. the input image is a stereoscopic image; and the viewpoint region corresponds to a motion state of the corresponding slave device, the master device further comprises a sensor sensing a motion state of the master device, the processor obtains relative motion information corresponding to the slave device by calibrating the motion information received from the slave device based on the sensed motion state, and identifies the viewpoint region corresponding to the motion state of the slave device based on the obtained relative motion information, and the processor is further configured to obtain the viewpoint region in a left-eye stereoscopic space image and a right-eye stereoscopic space image obtained by projecting a left-eye image and a right-eye image included in the input stereoscopic image into a virtual stereoscopic space.