In a controller which controls a reader for reading a radiographic image recorded in a cassette, a display controlling device is provided for the user to select one of three modes. The three modes are a pre-registration, a post-registration mode, and a non-registration mode. In the pre-registration mode, radiographing is conducted to acquire an image after the relationship between information of the body part to be radiographed and the cassette has been registered as radiographing reservation information. In the post-registration mode, an image is acquired after the relationship between information of the body part to be radiographed and the cassette insertion order has been registered as radiographing reservation information. In the non-registration mode, an image is acquired without registration of any relationship as radiographing reservation information and the following processes are continued according to the user's selected mode.