PURPOSE: To make it possible to pack even a soft ingredient of fibrous structure into another material while maintaining the ingredient almost in the original state in weighing a mixture of solid materials such as vegetable, fruit, etc., and injecting the mixture into another material such as bun, etc., by making the inner diameter of an injecting needle and that of a cylinder approximately equal.

CONSTITUTION: A mixture 20 of solid materials is weighed and injected into another material A. In the operation, the ingredient 20 is introduced into a cylinder 6 by a pushing device (e.g. rollers 2, pushing plates 3, cams 4, etc.) set in parallel with the cylinder 7 having a narrow and long opening 7', then the opening 7' of the cylinder 7 is closed and the ingredient 20 is pushed through an injecting needle 8 having approximately the same inner diameter as that of the cylinder 7 into the material A (by a piston 12).