A document searching device (100) comprises an inter-term weight calculation unit (130) and a weighting unit (140). The inter-term weight calculation unit (130) calculates, for each of two terms contained in a vector term comprising the terms contained by at least one of a plurality of search documents (210), an inter-term weight, which is the weight determined according to the semantic distance, the weight being for one term in the combination of the one term and another term when the one term is ranked lower than the other term. For each of the terms contained in the vector term, the weighting unit (140) determines the weight corresponding to each of the terms by using the inter-term weight and a search sentence feature amount corresponding to the search sentence when a vector term contains other terms ranked higher than each of the terms.