  We aim to explore the relationship between globular cluster total number,
$N_{\rm GC}$, and central black hole mass, $M_\bullet$, in spiral galaxies, and
compare it with that recently reported for ellipticals. We present results for
the Sbc galaxy NGC 4258, from Canada France Hawaii Telescope data. Thanks to
water masers with Keplerian rotation in a circumnuclear disk, NGC 4258 has the
most precisely measured extragalactic distance and supermassive black hole mass
to date. The globular cluster (GC) candidate selection is based on the ($u^*\
-\ i^\prime$) vs. ($i^\prime\ -\ K_s$) diagram, which is a superb tool to
distinguish GCs from foreground stars, background galaxies, and young stellar
clusters, and hence can provide the best number counts of GCs from photometry
alone, virtually free of contamination, even if the galaxy is not completely
edge-on. The mean optical and optical-near infrared colors of the clusters are
consistent with those of the Milky Way and M 31, after extinction is taken into
account. We directly identify 39 GC candidates; after completeness correction,
GC luminosity function extrapolation and correction for spatial coverage, we
calculate a total $N_{\rm GC} = 144\pm31^{+38}_{-36}$ (random and systematic
uncertainties, respectively). We have thus increased to 6 the sample of spiral
galaxies with measurements of both $M_\bullet$ and $N_{\rm GC}$. NGC 4258 has a
specific frequency $S_{\rm N} = 0.4\pm0.1$ (random uncertainty), and is
consistent within 2$\sigma$ with the $N_{\rm GC}$ vs. $M_\bullet$ correlation
followed by elliptical galaxies. The Milky Way continues to be the only spiral
that deviates significantly from the relation.
