1. A simulation system for simulating a function of a biological organ, the simulation system comprising: input means for receiving input of time-series actual measurement data representing biological response of a subject; reference data generating means for estimating the biological response of the subject at a time point at which the measurement is not made by using the input time-series actual measurement data, and generating time-series reference data representing the biological response of the subject; and virtual biological organ generating means for generating a virtual biological organ virtually constructed in a computer system using the times-series reference data, the virtual biological organ corresponding to a function of a biological organ of the subject.