The invention provides a plan execution control apparatus, a plan execution control method and a plan execution control program capable of giving instructions for sensitively and efficiently maintaining even installations located in a wide range. The plan execution control apparatus includes a linkage reliability calculating section for calculating a target reliability of a single or a plurality of mutually related installations, a damaged state transition control section that provides a damaged state transition structure of the installations, a maintenance time limit calculating section for calculating a time limit related to the maintenance work to meet the target level of reliability of each key point and section, the constraint control section for recognizing and recording the constraints related to traveling of maintenance personnel, the traveling workload and the acceptable workload, and the itinerary maintenance determining section for calculating the itinerary schedule indicating the assignment to the object to be maintained.