1. An imaging device, comprising: image input means for inputting an image of a subject; image signal processing means for processing the input image; display means for displaying on a display screen an input image processed by the image signal processing means; face detection means for detecting a face of the subject from the input image processed by the image signal processing means; target face setting means for setting one of the faces, detected by the face detection means, as a smiling face detection target; display control means for displaying, on a through image displayed by the display means, the detected face set by the target face setting means in a manner such that the set detected face is distinctly different from the other detected faces; and detection face changing means for changing the smiling face detection target to another detected face in response to a user operation performed on the display screen that displays the detected face set as the smiling face detection target and the other detected faces in the distinctly different manner.