In the text “Mass and Massiton”, I propose a hypothesis that there is one kind of the elementary particle that can produce gravitational force, and it is the minimum component that make up of mass, and I give it a name called “Massiton”. Both electrons and protons are composite particles, wherein the positive and negative charges are located at the center and the outer spherical shells wrapping the central electric charges are made up of Massitons. And the most convincing evidence for the existence of Massitons is the neutrinos that have mass, and have no charges.