A dark field lighting testing device, for detecting a surface defect of an
object having mirror surfaces, includes a cavity, the interior surface of
which is made of a light-absorbing material; an opening arranged on a top
of the cavity; a tape body arranged on the interior surface of the
cavity; a plurality of lighting elements arranged on the tape body and
electrically connected to each other; and a plate body arranged right
above the opening of the cavity. During testing procedure, light emitted
from each lighting element is incident upon the surface of the tested
object, from which the diffusively reflected or refracted light forms an
image on the surface of the plate body, thus a defect on the surface of
the tested body and a position thereof being able to be detected.