  We present measurements of the B+ meson total cross section and differential
cross section $d\sigma/ dp_T$. The measurements use a $98\pm 4$ pb^{-1} sample
of $p \bar p$ collisions at $\sqrt{s}=1.8$ TeV collected by the CDF detector.
Charged $B$ meson candidates are reconstructed through the decay $B^{\pm} \to
J/\psi K^{\pm}$ with $J/\psi\to \mu^+ \mu^-$. The total cross section, measured
in the central rapidity region $|y|<1.0$ for $p_T(B)>6.0$ GeV/$c$, is $3.6 \pm
0.6 ({\rm stat} \oplus {\rm syst)} \mu$b. The measured differential cross
section is substantially larger than typical QCD predictions calculated to
next-to-leading order.
