Fresnel lens and device for achieving narrow light emitting of non-point-light-source

The invention relates to a Fresnel lens which comprises a lens body. The improvement of the Fresnel lens lies in that the lens body is provided with a holding cavity, the bottom face of the holding cavity is an incident plane, the external surface of the lens body which is opposite to the incident plane is an exit plane, a central circular groove and a plurality of concentric annular tooth grooves are arranged on the incident plane, the bottom face of the central circular groove is a spherical surface, each annular tooth groove comprises a first surface perpendicular to the incident plane and a second surface intersecting with the first surface, the first surface and the second surface intersect to form an acute angle, and the exit plane is a spherical surface. The invention further provides a device for achieving narrow light emitting of non-point-light-source. The device comprises a non-point-light-source, the Fresnel lens and a reflection cup. By the aid of the Fresnel lens and the device, light emitting effect of small angle is achieved, and emitted light beam is guaranteed to be narrower.