PURPOSE: To obtain clear fresh soy sauce by squeezing and filtering aged unrefined soy through a filter fabric.

CONSTITUTION: A lifting frame 4 having a columnar space 3 with a cubic dimension of l1×l1×l1 is located below a tank 2 for unrefined soy 1 and a bottom plate 5 for this frame 4 is supported so as to allow to make vertical movements. The outlet 6 at the lower part of the tank 2 is provided with flow dividing plates 7 to divide the outlet for the unrefined say 1 into at least four suboutlets. The unrefined soy is then injected into a filter fabric 9a in four or more portions, and the vertical moving rate of the bottom plate 5 is set at ≤5mm/sec. Besides, the folding width for the filter fabric 9a is set at 30-50% of the width l1. Thereby, the unrefined soy is ensured not to contaminate at a level of ≥0.1wt.% in the final soy sauce. With this method, the leak of the unrefined soy can be brought to a minimum, thus ensuring a clear fresh say sauce to be obtained by being merely left standing.