PURPOSE: To obtain frozen lobster having excellent appearance and improve tractability in preserving and transporting processes and in retail sale by receiving each lobsters just before post-mortem rigidity in each groove-shaped depressed part, freezing with keeping an extended position and packaging with a tray and all.

CONSTITUTION: For instance, groove-shaped depressed parts 5 having V-letter like cross sectional shapes with holes 8 are provided in a synthetic resin tray 4 via divisions 7. Each lobster A dipped in cold brine (0-5°C) for 30-60min is received in each of the groove-shaped depressed part 5 in said tray 4 in straightly extended position with the abdomen side to below. Next, the lobsters are quickly frozen and packaged with the tray and all. Labor and cost for defrosting lobsters and subdividing are made unnecessary as the process uses a vessel for retail sale from the beginning.