A mixture filling apparatus comprising: a solid material supply unit that supplies a solid material; a liquid material supply unit that supplies liquid material; a hopper unit that is capable of storing and releasing the solid material supplied from the solid material supply unit and includes a hopper body and a shutter to open and close a release port of the hopper body; a weighing machine that is connected to the hopper unit and is configured to measure weight of the solid material stored in the hopper unit; a mixing tank that is configured to store the solid material supplied from the solid material supply unit via the hopper unit and the liquid material supplied from the liquid material supply unit, and receives the solid material released from the hopper unit when the release port of the hopper body is opened by the shutter; a mixture filling unit that is configured to fill a container with a mixture of the solid material and the liquid material stored in the mixing tank; and a control unit that is connected to the weighing machine and the liquid material supply unit, wherein the control unit is configured to control the liquid material supply unit to adjust an amount of the liquid material to be supplied from the liquid material supply unit according to a measurement result of the weighing machine, wherein the liquid material supply unit includes a discharge port to discharge the liquid material toward an inside of the hopper unit, wherein the discharge port is arranged to face toward at least one of an inner surface of the hopper body and an inner surface of the shutter, and wherein the control unit is configured to control the liquid material supply unit to discharge the liquid material from the discharge port after the solid material is supplied into the hopper unit from the solid material supply unit, the release port of the hopper body is opened by the shutter and the solid material enters the mixing tank from the inside of the hopper body via the release port. a solid material supply unit that supplies a solid material; a liquid material supply unit that supplies liquid material; a hopper unit that is capable of storing and releasing the solid material supplied from the solid material supply unit and includes a hopper body and a shutter to open and close a release port of the hopper body; a weighing machine that is connected to the hopper unit and is configured to measure weight of the solid material stored in the hopper unit; a mixing tank that is configured to store the solid material supplied from the solid material supply unit via the hopper unit and the liquid material supplied from the liquid material supply unit, and receives the solid material released from the hopper unit when the release port of the hopper body is opened by the shutter; a mixture filling unit that is configured to fill a container with a mixture of the solid material and the liquid material stored in the mixing tank; and a control unit that is connected to the weighing machine and the liquid material supply unit, wherein the control unit is configured to control the liquid material supply unit to adjust an amount of the liquid material to be supplied from the liquid material supply unit according to a measurement result of the weighing machine, wherein the liquid material supply unit includes a discharge port to discharge the liquid material toward an inside of the hopper unit, wherein the discharge port is arranged to face toward at least one of an inner surface of the hopper body and an inner surface of the shutter, and wherein the liquid material supply unit includes a discharge port to discharge the liquid material toward an inside of the hopper unit, wherein the discharge port is arranged to face toward at least one of an inner surface of the hopper body and an inner surface of the shutter, and wherein the control unit is configured to control the liquid material supply unit to discharge the liquid material from the discharge port after the solid material is supplied into the hopper unit from the solid material supply unit, the release port of the hopper body is opened by the shutter and the solid material enters the mixing tank from the inside of the hopper body via the release port.