A magnifying glass 1 captures an image of a tooth T by cameras 30 and 21 for observation. The cameras 30 and 21 include the narrow range camera 30 capturing an image of the tooth T in a narrow image capturing range An and the wide range camera 21 capturing an image of the tooth T in a wide image capturing range Aw. The magnifying glass 1 includes a three-dimensional position calculator 52 detecting a three-dimensional position of at least the tooth T based on a wide range image captured by the wide range camera 21； a blur correction processor 53 correcting a blur of a narrow range image captured by the narrow range camera 30, based on a change in a three-dimensional positional relationship between the tooth T, the three-dimensional position of which has been detected by the three-dimensional position detector 52, and the narrow range camera 30； and an image display portion 40 displaying at least the narrow range image having the blur corrected.
