PROBLEM TO BE SOLVED: To provide an ultraviolet-curable ink jet composition which can achieve both curability and storage stability at high levels.SOLUTION: An inkjet composition is stored in a storage body and comprises a polymerizable compound comprising a vinyl ether group and (meth) acryloyl group, wherein based on the total amount of the composition, the moisture amount is 0.05 mass% or more and 1.0 mass% or less.