A waterproof camera case includes first and second case members and a lock mechanism for locking the first and second case members together. The lock mechanism includes a side flip hingedly connected to a side of the rear case member and moveable between a flip open position and a flip closed position where an inner surface of the side flip abuts against a side of the front case member. A press member is pivotable about a first shaft mounted on the inner surface of the side flip and moveable between a non-pressing position and a pressing position. A free distal side of the press member is configured to press against a ledge projected from the side of the front case member on a surface oppositely facing the rear case member. A lock member is slidable along a second shaft mounted on the inner surface of the side flip and moveable between an unlocked position and a locked position. The lock member has a latch portion adapted to insert into a slot defined by a catch portion formed on the side of the front case member. A torsion spring is used to bias the press member in the non-pressing position, and a compression spring is used to bias the lock member in the locked position.