A lock device for an opening/closing device, is provided with: lock sections located on both sides of the lid; a pair of link rods provided with hook sections provided at the front ends of the pair of link rods; pressing means for pressing the hook sections in the direction in which the hook sections engage with the lock sections; a pusher for sliding the hook sections in the direction in which the hook sections do not engage with the lock sections; pressing members disposed on both sides of an opening and pressing the lid in the direction in which the lid opens; and a holding lever and a holding protrusion which hold the hook sections in a state in which the hook sections do not engage with the lock sections.