An IBIS correction tool which can be used assembled in a waveform simulation device and corrects IBIS data for a certain specific power supply voltage V0 to IBIS data for a desired power supply voltage V1 with a higher precision than the past, that is, an IBIS correction tool configured so as to read IBIS data for a power supply voltage V0 as numerical data of x-y coordinates at a data input unit, find a relative ratio (correction coefficient) between this numerical data and numerical data for a power supply voltage V1 on its x-y coordinates at a correction coefficient calculating unit, and obtain corrected IBIS data corrected for the power supply voltage V1 according to that correction coefficient at a corrected IBIS data generating unit.