PURPOSE: To prepare high quality lightly roasted bonito without peeling off of the surface layer of the fish meat while keeping its freshness, by cutting the frozen bonito into pieces, immersing the piece in hot water containing wood vinegar, and packing the treated bonito in vacuum.

CONSTITUTION: A bonito frozen at -40W-55°C is cut into pieces as frozen, and the frozen pieces are immersed in hot water containing 0.3W0.5% of wood vinegar at 55W70°C for 2W3 minutes. By this treatment, the proteins at the surface layer are coaqulated, and seasoned with the wood vinegar to the taste and flavor similar to the lightly roasted bonito. After the treatment, the bonito pices are vacuum- packed, and stored at -45W-55°C.