A graph display control device comprising: a display unit; a function graph display control unit which sets a coordinate system with a plurality of variables to control display of a function graph of the plurality of variables on the display unit; a point specifying unit which specifies an arbitrary point on the function graph as a specified point based on user operation; a true value judging unit which judges whether it is possible to display at least one of the variables of a coordinate value of the specified point in a true value state; a true value coordinate display control unit which controls display on the display unit to display at least one of the variables of the coordinate value in the true value state when the true value judging unit judges that at least one of the variables of the coordinate value can be displayed in the true value state; and a coordinate value display control unit which controls display on the display unit to display at least one of the variables of the coordinate value as a value within predetermined digits when the true value judging unit judges that at least one of the variables of the coordinate value cannot be displayed in the true value state; wherein a plurality of coordinate axes are set in directions different from each other in the coordinate system with the plurality of valuables, the graph display control device further comprising, a tracing pointer display control unit which controls display of a tracing pointer on the function graph, wherein, the point specifying section includes: a tracing pointer moving unit which moves the tracing pointer on the function graph in a predetermined coordinate axis direction which is a coordinate axis direction of the variable of the coordinate system based on user operation; and a tracing pointer point specifying unit which specifies a point of a coordinate as the specified point when it is possible to display a coordinate of the tracing pointer in the predetermined coordinate axis direction in the true value state, wherein in a case where the tracing pointer is moved in the predetermined coordinate axis direction by the tracing pointer moving unit, when the coordinate of the tracing pointer in the predetermined coordinate axis direction after movement of the tracing pointer cannot be displayed in the true value state, and there is a point between the positions of the tracing pointer before and after movement where the coordinate in the predetermined coordinate axis direction can be displayed in the true value state, the tracing pointer point specifying unit specifies the point as the specified point. a display unit; a function graph display control unit which sets a coordinate system with a plurality of variables to control display of a function graph of the plurality of variables on the display unit; a point specifying unit which specifies an arbitrary point on the function graph as a specified point based on user operation; a true value judging unit which judges whether it is possible to display at least one of the variables of a coordinate value of the specified point in a true value state; a true value coordinate display control unit which controls display on the display unit to display at least one of the variables of the coordinate value in the true value state when the true value judging unit judges that at least one of the variables of the coordinate value can be displayed in the true value state; and a coordinate value display control unit which controls display on the display unit to display at least one of the variables of the coordinate value as a value within predetermined digits when the true value judging unit judges that at least one of the variables of the coordinate value cannot be displayed in the true value state; wherein a plurality of coordinate axes are set in directions different from each other in the coordinate system with the plurality of valuables, the graph display control device further comprising, a tracing pointer display control unit which controls display of a tracing pointer on the function graph, wherein, the point specifying section includes: a tracing pointer moving unit which moves the tracing pointer on the function graph in a predetermined coordinate axis direction which is a coordinate axis direction of the variable of the coordinate system based on user operation; and a tracing pointer point specifying unit which specifies a point of a coordinate as the specified point when it is possible to display a coordinate of the tracing pointer in the predetermined coordinate axis direction in the true value state, a tracing pointer moving unit which moves the tracing pointer on the function graph in a predetermined coordinate axis direction which is a coordinate axis direction of the variable of the coordinate system based on user operation; and a tracing pointer point specifying unit which specifies a point of a coordinate as the specified point when it is possible to display a coordinate of the tracing pointer in the predetermined coordinate axis direction in the true value state, wherein in a case where the tracing pointer is moved in the predetermined coordinate axis direction by the tracing pointer moving unit, when the coordinate of the tracing pointer in the predetermined coordinate axis direction after movement of the tracing pointer cannot be displayed in the true value state, and there is a point between the positions of the tracing pointer before and after movement where the coordinate in the predetermined coordinate axis direction can be displayed in the true value state, the tracing pointer point specifying unit specifies the point as the specified point.