To suppress the scattering or deformation by oxidation of a component of coffee such as aromatic material which is said to be unstable and quickly changed with the lapse of time, and efficiently provide a dense coffee extract usable as raw liquids for business use having a high dilution or for manufacture of refreshing drinks.

Ground coffee is put in an extracting vessel 3 and sealed, water supply and extraction are performed after the device is internally deaerated, and the extract is sucked and filtered by utilizing the flexible structure by a bag 5 and the press caused by the atmospheric pressure difference between the inside and outside of the extracting vessel 3.