A delivery plan creating device includes: a delivery request acquisition unit that acquires a delivery change request; a change instruction deadline calculation unit that calculates, based on a delivery time range contained in the delivery change request, a change instruction deadline representing a deadline that can instruct a change in a delivery plan; a storage unit that stores conditional calculation record information in which a delivery condition set at a time of creating an executed delivery plan is in association with calculation time required for creating the executed delivery plan; a search unit that selects a delivery condition set similar to the delivery change request from the conditional calculation record information; and a calculation starting time point calculation unit that calculates a calculation starting time point by counting the calculation time in association with the selected delivery condition set backward from the change instruction deadline.