This optical unit comprises: a fixed part that has a cylindrical shape for holding at least one of an object-side fixed lens group and an image-side fixed lens group, with a plurality of thin sections formed at regular intervals at positions symmetrical about the center axis of the cylindrical shape a cylindrical movable part that holds a movable lens group between the object-side fixed lens group and the image-side fixed lens group, is disposed on the radial inner side of the fixed part so as to be slidable with respect to the fixed part, and has the same center axis as the fixed part and a voice coil motor that has a coil disposed on the fixed part and a plurality of magnets disposed on the movable part so as to be magnetically polarized in directions intersecting the center axis, disposed substantially symmetrical about the center axis and disposed on the movable part so as to be respectively inserted into the thin sections of the fixed part, said voice coil motor being capable of moving the movable part relative to the fixed part along the center axial direction. Among the plurality of magnets, at least two circumferentially adjacent magnets in a cross section perpendicular to the center axis are disposed more toward each other in the circumferential direction.Lunité optique de linvention est équipée : dune partie fixe qui prend une forme tubulaire maintenant au moins un groupe de lentilles fixes côté objet ou un groupe de lentilles fixe côté image, et dans laquelle une pluralité de parties évidées est formée à intervalles réguliers en des positions symétriques par rapport à laxe central de la forme tubulaire dune partie mobile qui maintient un groupe de lentilles mobiles entre le groupe de lentilles fixes côté objet et le groupe de lentilles fixe côté image, qui est disposée côté interne dans la direction radiale de la partie fixe de manière à permettre un coulissement vis-à-vis de la partie fixe, et qui présente une forme tubulaire possédant le même axe centra
