A flow-data generation apparatus comprises a first unit extracting first binomial relation data to be a start point, a second unit associating second term of the first binomial relation data as a first child node with the start point as a first parent node, a third unit adding a relation type to an arc of the first binomial relation data, a fourth unit searching for third binomial relation data including first term of the third binomial relation data identical to second term of second binomial relation data, a fifth unit associating second term of the third binomial relation data as a second child node with the first term of the third binomial relation data as a second parent node, a sixth unit adding a relation type to an arc of the third binomial relation data, and an seventh unit repeating the searching, associating, and adding to generate a partial tree.