A random number generator capable of generating a natural random number using a spin-orbit torque (SOT) is provided. The random number generator includes a ferromagnetic metal layer and a spin-orbit torque wiring extending in a first direction crossing a lamination direction of the ferromagnetic metal layer and being joined to the ferromagnetic metal layer, wherein the direction of spins injected from the spin-orbit torque wiring into the ferromagnetic metal layer and an easy magnetization direction of the ferromagnetic metal layer intersect each other.