  We study a possibility of the Higgs boson, which consists of an SU(2) doublet
and a septet. The vacuum expectation value of a septet with hypercharge Y=2 is
known to preserve the electroweak rho parameter unity at the tree level.
Therefore, the septet can give significant contribution to the electroweak
symmetry breaking. Due to the mixing with the septet, the gauge coupling of the
standard-model-like Higgs boson is larger than that in the standard model. We
show the sizable VEV of the Higgs septet can be allowed under the constraint
from the electroweak precision data. The signal strengths of the Higgs boson
for the diphoton and a pair of weak gauge boson decay channels at the LHC are
enhanced, while those for the fermonic decay modes are suppressed. The mass of
additional neutral Higgs boson is also bounded by the current LHC data for the
standard model Higgs boson. We discussed the phenomenology of the multiply
charged Higgs bosons, which come from the septet.
