There is provided a focusing device capable of rapidly moving a lens to a minute focusing region and of realizing minute movement of focusing the lens in the minute focusing region. A lens moving mechanism comprises a first guide portion for guiding a lens to move in an optical-axis direction by a first predetermined distance to a minute focusing region and a second guide portion for guiding the lens 5 to minutely move in an optical direction by a second predetermined distance in the minute focusing region. The first guide portion is comprised of inclined portions 8a12 and 8a22 of guide grooves 8a1 and 8a2 of the outer cam 8. The second guide portion is comprised a first cam 4a1 and a second cam 4a2 of a lens holder 4.