A panic exit door lock includes an outer operational device mounted to an outer side of a door, an inner operational device mounted to an inner door of the door, a lock mounted in the door, and a locking mechanism mounted between the inner and outer operational devices and the lock. The locking mechanism includes an outer cylinder mounted to the outer operational device and an inner cylinder mounted to the inner operational device. An indicator member is operably connected to the inner cylinder and a setting member. The setting member is connected to a transmission block. When a key is used to set a locking function of the inner or outer cylinder, the transmission block and the indicator member pivot jointly. A user can see whether the locking function is set by observing the position of the indicator member via a window of an inner cylinder seat.