PROBLEM TO BE SOLVED: To provide a growth method of seaweed seedlings, capable of stably surely fixing a seaweed-adhered string body and stably and efficiently growing seaweed seedlings.SOLUTION: A groove portion 11 is formed on a surface of a substrate plate 1 including a polyester knitted fabric laminated on a glass mat and integrated thereto by an unsaturated polyester resin, and the seaweed-adhered string body 2 is inserted to the groove portion 11. After the string body 2 is inserted to the groove portion 11, the string body 2 is fixed to the substrate plate 1 by a rubber band 3 and fixed also to the groove portion 11 by an adhesive 4. The substrate plate 1 with the string body 2 being fixed to the groove portion 11 by the rubber band 3 and adhesive 4 is immersed in culturing water to grow seaweed seedlings.COPYRIGHT: (C)2013,JPO&INPIT【課題】海藻付き紐状体を基質プレートに安定的かつ確実に固定して、海藻種苗を安定的かつ効率良く育成できる海藻種苗の育成方法を提供すること。【解決手段】ガラスマットの上にポリエステル編地を積層して不飽和ポリエステル樹脂により一体化した基質プレート1の表面に溝部11を形成して、その溝部11に海藻付き紐状体2を挿入し、海藻付き紐状体2を溝部11に挿入した後、海藻付き紐状体2と基質プレート1をゴムバンド3で固定すると共に、接着剤4で海藻付き紐状体2を溝部11に固定し、海藻付き紐状体2がゴムバンド3および接着剤4で溝部11に固定された基質プレート1を培養水に浸けて海藻種苗を育成する。【選択図】図4