The Doll Key is a key that is obtained in Silent Hill 4: The Room. Henry Townshend must obtain it in order to unlock Room 303 of South Ashfield Heights during his first visit to the Apartment World. Room 303 belongs to his neighbor Eileen Galvin, and Henry seeks to enter her apartment believing she is in danger.
The key location beside Henry's bed (only appears after reading red memo).
The key, however, is not located with the other apartment keys held by the superintendent, and Henry must instead follow a clue from a diary indicating that the key is hidden in the bedroom of his apartment to the right of the bed. The diary page that triggers the key to appear can be found inside Room 102, inside the kitchen refrigerator. It can be hard to find if the player doesn't check every fridge, something that will likely happen, since most fridges in the game can't be opened.
The key is named for the small doll attached, which is identical to the Shabby Doll, another item obtainable in the Apartment World.