The net oral inclined maintenance type trawl net collection device which autonomously controls attitude is offered. It is formed by the side net of the upper net and the backing wire and pair, with the resistance and lift of the water flow for the net the side where the side net of the aforementioned itself section the long side has the side shortly in the side of the top and bottom in the trawl net which possesses the form which consists of with the substance section of four pyramid trapezoids and the cot ended section which is connected to the point of the said four pyramid trapezoids, forms the net oral edge, the description above shortly base and tilt angle of skew of the side net leading edge where the below-mentioned formula of the isopodous trapezoid which designates the side as the leg shortly (1) satisfies relationship ( ) by forming, the net mouthThe leading edge tried to maintain tilt angle of skew ( ) autonomously.自律的に姿勢を制御する網口傾斜維持型トロール網採集装置を提供する。上網と下網と一対の側網によって形成され、四角錐台形の本体部と該四角錐台形の先端に接続されたコットエンド部とからなる形状を有するトロール網において、前記本体部の側網は、上下の辺に長辺と短辺を有し、網口縁をなす辺が、前記短辺を短脚とする等脚台形の底辺と、下記の式(1)の関係を満たす側網前縁の傾斜角(γ)をなすことにより、網に対する水流の抵抗と揚力により網口の前縁が傾斜角(β)を自律的に維持するようにした。
