A data placement device creates a similarity index for each of computational resources based on a similarity between each of the pieces of acquired data and each of the pieces of data stored in the computational resources. The data placement device allocates on the basis of the similarity index of each of the computational resources with respect to the pieces of the data, the pieces of the data to each of the computational resources by using a matching system in which the similarity index associated with each allocation becomes stable in a direction in which the similarity index is small. The placement device places the pieces of the acquired data into the computational resources on the basis of the allocation result.