In this paper, we derive the existence of elementary particles from the law of creation. This work confirms and derives from the fundamental principle Xiao Gang Wen's result that string-net condensation is a way to generate elementary particles and unify light and electrons. In our previous work, we proposed the law of creation. We derived string theory, M theory, and the wave function of our universe from this fundamental law. We show that one can explain the expanding universe, dark matter, dark energy, the large structure of the universe, inflation, and the laws of physics related to gravity, weak and strong forces, and electromagnetism. In this paper, we show how to derive the existence of elementary particles and how to explain the wave-particle duality of elementary particles from the law of creation. We show that a string-like action creates the vibrational field of our universe. Due to the Poincaré invariance in the string-like action, elementary particles emerge from the vibrational field of our universe. As the different representations of Poincaré symmetry, elementary particles have specific still mass and spin. This explains the wave-particle duality of elementary particles.