To provide a reusable plastic freezing container which is free from danger of damaging frozen seafood therein, and is easy to take out of a metal container.

The plastic freezing container A, designed to be disposed within the tray-like metal container B so as to freeze the seafood quickly, includes a tray-like container body 1 which is disposed along the bottom wall b1 and the peripheral wall b2 of the metal container B so as to be arranged within the metal container B, and includes an opening flange part 4 which overlaps and covers the opening marginal part 3 of the metal container B on the upper opening edge of the container body 1. In addition, the container is provided with a lid body 2 to close the opening of the container body 1.