A coordinate calculator includes: an image processing unit configured to calculate a coordinate of an attention point from each of a plurality of images captured by a plurality of imaging units; a transmitter configured to transmit the calculated coordinate to a connected separate information processing device using a built-in function included in an operating system of the information processing device; a receiver configured to receive calibration information of the imaging unit, the calibration information being calculated by the information processing device based on the transmitted coordinate and transmitted by the information processing device using a built-in function included in the operating system of the information processing device; and a storage unit configured to store therein the received calibration information.