PROBLEM TO BE SOLVED: To provide means that maintains artificial breeding of firefly larvae while reducing a work load of management and maintenance of shellfish serving as bait of the firefly larvae, feeding work to the firefly larvae, etc.SOLUTION: A firefly larvae breeding system A includes: a shellfish growing area 1 for growing shellfish S serving as bait of firefly larvae N； a firefly larvae growing area 2 formed in the upstream X1 side of the shellfish growing area 1, substantially isolated from the shellfish growing area 1 by the circumference being surrounded with a sidewall 21, and having freshwater W1 stored inside； and freshwater supply means 3 for supplying the freshwater in the storage water W1 of the firefly larvae growing area 2. In the firefly larvae breeding system, the overflowing freshwater by making overflow of the sidewall 21 from the firefly larvae growing area 2 flows into the shellfish growing area 1 after streaming down an outer wall face of the sidewall 21 (signs W3, W4), and the case when the freshwater makes the overflow and does not make the overflow of the sidewall 21 can be controlled for each of time.SELECTED DRAWING: Figure 1【課題】ホタル幼虫の餌となる貝類の管理・維持、ホタル幼虫への給餌作業などの作業負担を軽減しつつ、ホタル幼虫の人工飼育を維持する手段の提供。【解決手段】ホタル幼虫Nの餌となる貝類Sが生育する貝類生育領域1、貝類生育領域1の上流X1側に形成され、側壁21で周囲が取り囲まれることで貝類生育領域1から略隔離され、内部に淡水W1が貯留されたホタル幼虫育成領域2、及び、ホタル幼虫育成領域2の貯留水W1中に淡水を供給する淡水供給手段3を備え、ホタル幼虫育成領域2から側壁21を越流して溢れ出る淡水が、側壁21の外壁面を伝ってから貝類生育領域1へ流れ込み（符号W3、W4）、かつ、淡水が側壁21を越流する場合と越流しない場合を時間ごとに調節できるホタル幼虫育成システムAなどを提供する。【選択図】図１
