Apparatus and method for circuit diagram display, and computer product

A circuit diagram display apparatus displays a plurality of logic circuit diagrams. An associating unit associates the logic circuits based on at least any one of identification information, structural information, logical equivalence information, and external designated information about the logic circuits. A display format changing unit changes a display format between a side-by-side format and one-below-the-other format. A display controller performs control to display a target point in the logic circuit diagram in the same position before and after the display format is changed.