In a search schedule determining apparatus, a target probability distribution showing a distribution of probabilities of positions of a target in a time zone is calculated based on target previous information. A search ability showing a quantitative evaluation of an ability to discover the target is calculated based on search vehicle previous information. A search effort distribution is calculated based on the target probability distribution and the search ability such that a combination of probabilities in which each of the search vehicles discovers the target has a maximum. A search schedule is automatically determined based on the target previous information and the search vehicle previous information such that the search vehicles are operated to realize the search effort distribution.