A monitoring camera has a base, a camera module and a casing. The base has a parapet formed on the base. The parapet has a memory slot and at least one pair of guide slots formed oppositely on the parapet. Each guide slot has a notch extending toward the bottom of the parapet. The casing corresponds to and covers the parapet and has at least one pair of guide protrusions formed on the casing. The guide protrusions respectively engage corresponding guide slots. When unscrewing the casing, the guide protrusions will correspondingly move and be mounted in the notches and the memory slot is accessible. Therefore, the casing need not to be completely detached from the base to allow a removable memory to be installed or removed easily.