PURPOSE: To prepare dried sheet having excellent quality, continuously and efficiently, by cutting raw laver to small pieces, diluting the obtained raw material of laver sheet with a specific dilution water, and making the slurry in the form of a sheet.

CONSTITUTION: Fresh water supplied from the water tank 2 to the mixing tank 1 is mixed with sea water of about 3% concentration and an alkaline solution (e.g. NaHCO3 solution) supplied from the tanks 3, 4, and the electrical conductivity and the pH of the mixture are measured by the cells 12, 13 and adjusted to about 8. The obtained dilution water is supplied through the pipe 19 to the raw material mixer 17, in which the water is mixed with the cut raw laver supplied from the raw material tank 23. The resultant mixture is supplied through the pipe 20 to the raw material tank 18, stirred with a stirrer 27 to form a slurry, and made to a sheet by a paper-making machine. The luster of the laver sheet can be improved and the loss of flavor can be prevented by MgSO4 existing in sea water, the deterioration of the taste can be prevented by CaCl2, and the delicious taste of the laver sheet can be increased by NaCl. A dried laver sheet having good luster and dark purple color can be prepared by this process.