To provide an electric rate provisional calculation device capable of provisionally calculating easily an electricity rate in a prescribed period, based on an optional charge system.

This electric rate provisional calculation device capable of calculating provisionally the electricity rate in the prescribed period is provided with a classification part for classifying a correlation between a date and a time in the prescribed period into individual correlations of applying different electric rate unit prices, an individual calculation part for calculating the electricity rate in every of the individual correlations, based on the different electric rate unit prices, and a total calculating part for totalizing the electricity rates in the respective individual correlations.