The present invention relates to a fish processing device and, more specifically, to a fish processing device capable of improving productivity and enhancing quality by being able to cleanly, uniformly, and smoothly process fish such as anchovy and the like. According to the present invention, the fish processing device comprises: a heating tank having a heating space in which water is contained, having a closed shape to be isolated from the outside except one end and the other end of an upper part, having an inlet formed at one end of the upper part, and having an outlet installed at the other end of the upper part to have the other side and the upper side which are opened; a boiler installed at the lower part of the heating tank, and heating the water; an input means for inserting a plurality of trays in which fish is contained and which are stacked in vertical layers into one end of the heating tank by downwardly vertically moving the trays onto the inlet; a transfer means installed in the heating tank, tr
