Although glueballs, as one of the type of exotic hadrons allowed by QCD, have been well established on the lattice, experimental searches up to this date for bound states of gluons have only produced controversial signals. In this work, using flavor SU(3) symmetry for the light quarks validated by the available experimental data, we propose an intuitive way to hunt for a scalar glueball in exclusive B decays. In the presence of mixing between the glueball and ordinary scalar mesons, we point out that the scalar glueball content amounts to the ratio of B-decay branching fractions. We discuss the implication from the recently available experimental data and show the sensitivities of B decays as a probe to the scalar structures. The on-going LHCb experiment and forthcoming Super KEKB factory would allow access to precisely establishing the mixing pattern among the scalars, and may allow one to disentangle the long-standing puzzle concerning the existence and mixings of the scalar glueball predicted by QCD.