A lock apparatus includes a lid configured to turn to open and close an opening of a box; a rod switchable between a locked position where a tip of the rod projects to outside of the lid and an unlocked position where the tip is retracted to inside of the lid; and a guide member attached to the inside of the lid and configured to slidably support the rod. The lid includes one of an engaging portion and an engaged portion, and the guide member includes another of the engaging portion and the engaged portion. The engaging portion and the engaged portion are configured to move the guide member in a direction intersecting a lid opening and closing direction to thereby fix and press-fit to each other without rattle.