To eliminate the wrong combination in a plate valve formed by combining a plurality of valve plates with gaskets.

Valve plates 1-5 have combination confirming recessed parts 15-24 which are regularly arranged alternately in the superposing direction in the normal superposition of the valve plates 1-5 on the side surfaces, respectively. On the other hand, gaskets 12-15 have wrong combination checking recessed parts 24-27 whose relative positions are conformed to the combination confirming recessed parts 15-24 in the normal combination thereof.