Data display apparatus, method and program, and data structure and recording medium

When plural datasets each composed of a set of numerical value data respectively corresponding to plural values on a variable axis common to the datasets are displayed on a display screen, they are displayed in a display mode of a graph mode or a table mode in such a manner that they are vertically arranged with a horizontal axis representing the variable axis coinciding with each other. An input of instruction for switching the display mode for at least one of plural partial display areas in which the datasets are displayed is received. The partial display area for which the input of instruction has been received is set so that its height becomes a height for the switched display mode stored in advance in such a manner to be linked with the partial display area. The set partial display area is displayed in the switched display mode.