1. A task allocation optimization system, comprising: a state evaluation function value generation unit configured to generate a state evaluation function value, for each operating state, based on a state/task-set correspondence table and a task set parameter, the state/task-set correspondence table, indicating correspondence of a list of operating states that change according to a state of a system and a task set that is a set of a plurality of tasks being operated in each of the operating states, where the system is comprised of a plurality of processor-cores, the task set parameter that indicates a characteristic of each task constituting the task set, and the state evaluation function value that is an evaluation value indicating a degree of quality of task allocation for a plurality of task allocation candidates respectively when each task of the operating states is allocated to the plurality of processor-cores; an integrated evaluation function value generation unit configured to generate an integrated evaluation function value, for each task allocation candidate, in which the state evaluation function value of each operating state is integrated, the integrated evaluation function value being an evaluation value indicating a degree of quality for a whole of the system; and an optimal allocation search unit configured to optimize allocation of a task to be allocated to each of the plurality of processor-cores by searching for an allocation candidate with the highest degree of quality of the integrated evaluation function value from the plurality of task allocation candidates, wherein, the task set parameter includes an execution time in each task, the state evaluation function value generation unit calculates a total value by summing up the execution time for each of the plurality of processor-cores which each task is allocated as the allocation candidate, and uses one of the group consisting of i) an absolute value of a difference between the total values of the processor-cores as the state evaluation function value, and ii) a square of a difference between the total values of the processor-cores as the state evaluation function value, when the state evaluation function value is smaller, the degree of quality is higher, and the optimal allocation search unit selects the allocation candidate having a small integrated evaluation function value preferentially as optimal allocation.