The cooling fluid passage F may be formed between the first plate P1 formed for each separate accommodation space G and the second plate P2 arranged to face the first plate P1 and may be formed between the first exposure portion P1b of the first plate P1 and the second exposure portion P2b of the second plate P2. Here, the first exposure portion P1b may define a side of the cooling fluid passage F in the third direction Z3, and the second exposure portion P2b may define the other side of the cooling fluid passage F in the third direction Z3.