PROBLEM TO BE SOLVED: To provide a laver production device capable of inverting a laver mat holder on which a laver mat is held, with good work ability and with a simple structure.SOLUTION: A holder inversion part 14 is disposed on a lower stage transport path 2L for forming holder transport means and inverts a laver mat holder 5 on which plural laver mats are held. The holder inversion part 14 is configured so that, a support member 22 for supporting the laver mat holder 5 held to a lower face side of an endless chain 3 from the lower face side is rotated in a direction where a downstream side of the transport direction sags, and the laver mat holder 5 is also sagged with the support member 22, and a rod part 6b of an upstream side in the transport direction of the laver mat holder 5 is held from the lower face side by a support tool 34c, then is moved by a predetermined locus, and is engaged to an engagement part 4 on a downstream side by one stage, namely replacement of engagement is performed, and the rod part 6b is directed to the downstream side, the endless chain 3 moves the laver mat holder 5 for guiding the holder 5 in a state that the front and rear sides of the holder 5 are inverted to the lower stage transport path 2L.