Latch device for vehicle back door

A vehicle back door latch device having a striker fixed to one of a vehicle body and a vehicle back door, and a latch assembly fixed to the other of the vehicle body and the vehicle back door, said latch assembly comprising;

• a latch engaged with the striker for holding a closed state of the back door when closed;
• a main metal plate having a vessel-shaped storing portion for storing the latch, said storing portion being defined by a bottom wall, a front wall, a rear wall, a right-hand wall and a left-hand wall;
• a sub metal plate fixed to the main metal plate so that an upper opening of the storing portion is covered by the sub metal plate;
• a main notch portion formed in the bottom wall for receiving the striker when the back door is closed;
• a sub notch portion formed in the front wall for receiving the striker when the back door is closed;
• and
• first engaging means located on both sides of the sub notch portion of the front wall and second engaging means located on said striker for preventing separation of said front wall adjacent to said sub notch portion and said bottom wall adjacent to said main notch portion when said back door is closed and said latch device is, impacted by a force.