Lens barrel, camera and information device

A lens barrel, comprising:

• a plurality of lenses;
• a plurality of lens frames each of which holds respectively at least one lens of the plurality of lenses;
• a fixed member;
• a rotating member which rotates to move the lens frames to predetermined positions, the rotating member being fitted in an inner circumferential surface of the fixed member and being rotated relative to the fixed member, wherein the rotating member does not move relative to the fixed member in the direction of the optical axis while rotating relative to the fixed member in at least a photographing state;
• cam followers each provided on the lens frames;
• and
• cams each provided on an inner circumferential surface of the rotating member and each having a cam surface, the cams each being engaged with the corresponding cam followers and each forming a cam locus,
• wherein, in the photographing state, the cam locus on an object side of one of the cams engaged with one of the cam followers corresponding to a first lens frame as a first cam forms a part following along a direction perpendicular to the optical axis, and the cam locus on an image plane side of the first cam facing the cam locus on the object side has an angle to the direction perpendicular to the optical axis.