An ontology creation apparatus according to an embodiment includes: a first selection unit that receives an input operation that is performed based on information that represents definitions of candidate classes of ontology; an acquisition unit that acquires a candidate class of a subject when the selected class is determined as the object, based on information that represents definitions of properties that indicate connection relationships between classes that serve as objects and classes that serve as subjects; a second selection unit that receives an input operation for selecting an instance that belongs to a class of a subject when the selected class is determined as an object, based on the candidate; a relationship setting unit that sets a connection relationship between instances that belong to the selected class and the selected instance; and an output unit that creates and outputs ontology that indicates the selected class, the instance, and the set connection relationship.