Provided are electrolytic solution absorbing particles that have an electrolytic solution retention property and can increase a lithium ion transport characteristic, as well as a self-supporting sheet that includes the same, a lithium-ion secondary battery electrode that includes the same, a separator that uses the same, and a lithium-ion secondary battery that uses the same. These particles are particles wherein a resin layer that can absorb an electrolytic solution is provided on a surface of a highly dielectric oxide solid. Specifically, these particles are electrolytic solution absorbing particles that have the resin layer that can absorb the electrolytic solution on the surface of the highly dielectric oxide solid.