An information management device includes a memory, and processing circuitry coupled to the memory and configured to convert said spatio-temporal information in storage object information into a one-dimensional bit string, split the converted one-dimensional bit string into an upper bit string and a lower bit string, and cause a storage target node to store at least the split upper bit string in a key and to store the split lower bit string and said associated data in a value of that key, and convert a range condition of spatio-temporal information of an object to be retrieved into one-dimensional bit string, split the converted one-dimensional bit string into an upper bit string and a lower bit string, retrieve a key from a search target node using at least the split upper bit string, and retrieve a value corresponding to the split lower bit string from values of the retrieved key.