A current position computation unit of a hydraulic shovel computes a current position of a working point included in a work tool based on a plurality of parameters that indicate the dimensions and swing angles of a boom, an arm, and the work tool. A vehicle body coordinate system computation unit of a calibration device computes coordinate conversion information based on first and second working point position information measured by an external measurement device. A coordinate conversion unit converts coordinates at a plurality of positions of the working point measured by the external measurement device in a coordinate system of the external measurement device to those in a vehicle body coordinate system using the coordinate conversion information. A calibration computation unit computes calibration values of the parameters based on the converted coordinates at the plurality of positions of the working point in the vehicle body coordinate system.