A production method for producing a particle mixture in which two or more types of particles are mixed, the production method comprising: a step of adding a first additive to first particles and mixing the first additive with the first particles using a first mixer; and a step of introducing the two or more types of particles including the first particles mixed with the first additive and second particles into a blender container of a gravity blender, and mixing the two or more types of particles inside the blender container, wherein the blender container is provided with an inlet in an upper portion and an outlet in a lower portion, a downstream portion of the outlet is connected to a conveyance route that extends to the inlet, the step of mixing the two or more types of particles inside the blender container includes, a step of mixing the two or more types of particles while allowing the two or more types of particles to fall from the inlet to the outlet with the force of gravity, and then conveying the two or more types of particles from the outlet to the inlet in order to mix the two or more types of particles again while allowing the two or more types of particles to fall from the inlet to the outlet with the force of gravity, thereby making the two or more types of particles circulate in the blender container and the conveyance route, and the number N of circulation times of the two or more types of particles satisfies 1.5<N<2.5, wherein N is defined by an equation N=N2·t/N1, where N1 is the total amount of the two or more types of particles, N2 is the flow rate of the two or more types of particles that have passed through the conveyance route, and t is the circulation period. a step of adding a first additive to first particles and mixing the first additive with the first particles using a first mixer; and a step of introducing the two or more types of particles including the first particles mixed with the first additive and second particles into a blender container of a gravity blender, and mixing the two or more types of particles inside the blender container, wherein the blender container is provided with an inlet in an upper portion and an outlet in a lower portion, a downstream portion of the outlet is connected to a conveyance route that extends to the inlet, the step of mixing the two or more types of particles inside the blender container includes, a step of mixing the two or more types of particles while allowing the two or more types of particles to fall from the inlet to the outlet with the force of gravity, and then conveying the two or more types of particles from the outlet to the inlet in order to mix the two or more types of particles again while allowing the two or more types of particles to fall from the inlet to the outlet with the force of gravity, thereby making the two or more types of particles circulate in the blender container and the conveyance route, and the number N of circulation times of the two or more types of particles satisfies 1.5<N<2.5, wherein N is defined by an equation N=N2·t/N1, where N1 is the total amount of the two or more types of particles, N2 is the flow rate of the two or more types of particles that have passed through the conveyance route, and t is the circulation period.