The invention discloses a quick freezing device for aquatic products, and relates to the aquatic product processing technology field. The quick freezing device for the aquatic products comprises a freezing box and a liquid nitrogen supply device, wherein a collection hopper communicating with the interior of the freezing box is arranged on the side wall of the freezing box, a drainage mechanism located above a conveying mechanism is arranged in the freezing box, the conveying mechanism comprises a conveying belt, gas guide holes are evenly formed in the conveying belt, and a rotary jet mechanism communicating with the liquid nitrogen supply device is arranged in the conveying mechanism. By jetting liquid nitrogen generated by the liquid nitrogen supply device through a fixed spray head from the top down and through a rotating spray head from the bottom up, the quick freezing device for the aquatic products realizes full contact between the liquid nitrogen and the aquatic products on the conveying belt, and greatly improves freezing rate of the aquatic products, and by arranging a flexible cutting plate for separating the aquatic products on the conveying belt, the quick freezing device for the aquatic products effectively prevents the aquatic products from piling, guarantees that the aquatic products are fully frozen by the liquid nitrogen, and greatly improves freezing effectof the aquatic products.