  We analyze the ${\it Kepler}$ monitoring light curve of a blazar W2R
1926$+$42 to examine features of microvariability by means of the "shot
analysis" technique. We select 195 intra-day, flare-like variations (shots) for
the continuous light curve of Quarter 14 with a duration of 100 d. In the
application of the shot analysis, an averaged profile of variations is assumed
to converge with a universal profile which reflects a physical mechanism
generating the microvariability in a blazar jet, although light-variation
profiles of selected shots show a variety. A mean profile, which is obtained by
aligning the peaks of the 195 shots, is composed of a spiky-shape shot
component at $\pm$0.1 d (with respect to the time of the peak), and two slow
varying components ranging from $-$0.50 d to $-$0.15 d and from 0.10 d to 0.45
d of the peak time. The former spiky feature is well represented by an
exponential rise of 0.043$\pm$0.001 d and an exponential decay of
0.061$\pm$0.002 d. These timescales are consistent with that corresponding to a
break frequency of a power spectrum density calculated from the obtained light
curve. After verification with the Monte-Carlo method, the exponential shape,
but not the observed asymmetry, of the shot component can be explained by noise
variation. The asymmetry is difficult to explain through a geometrical effect
(i.e. changes of the geometry of the emitting region), but is more likely to be
caused by the production and dissipation of high-energy accelerated particles
in the jet. Additionally, durations of the detected shots show a systematic
variation with a dispersion caused by a statistical randomness. A comparison
with the variability of Cygnus X-1 is also briefly discussed.
