1. A confocal microscope comprising: a light source; a scanning device for two-dimensionally scanning light from said light source on a specimen; an objective lens arranged between said scanning device and the specimen; a driving device for moving said objective lens and the specimen relative to each other in an optical axis direction of said objective lens; a control circuit for simultaneously driving said scanning device and said driving device, and controlling a scanning speed of said scanning device and a moving speed of said driving device; an image acquisition device for detecting light from the specimen while said scanning device and said driving device are being driven simultaneously, and acquiring slice images of the specimen on planes respectively perpendicular to two inclined axes which are symmetrical about the optical axis or an axis inclined from the optical axis; and a display device for displaying a stereoscopic image of the specimen on the basis of the images acquired by said image acquisition device.