The invention provides an optical scanning device and an electronic imaging device, the unit comprises a light source; an optical deflector; an imaging optical system for guiding a light beam deflected by the optical deflector to a surface to be scanned for imaging; wherein the imaging optical system includes an F-theta lens satisfying: fc/fs <=0.6, X1-X1c >0, X2-X2c >0, wherein, fc is an f-thetacoefficient of the F-theta lens; fs is a focal distance of the F-theta lens; X1 is the distance between the projection of any incident point on a main optical axis and a scanning origin point; X2 is the distance between the projection of any emergent point on the main optical axis and the scanning origin point; X1c is the distance between the center incident point and the scanning origin point; X2c is the distance between the central exit point and the scanning origin point, so that the possibility of image distortion and linear scanning performance deterioration is reduced, the volume miniaturization is achieved, the scanning imaging accuracy is improved, and the image quality is improved.