  We study the finite-temperature electroweak phase transition of the minimal
standard model within the four-dimensional SU(2) gauge-Higgs model. Monte Carlo
simulations are performed for intermediate values of the Higgs boson mass in
the range $50 \lesssim M_H \lesssim 100$GeV on a lattice with the temporal size
$N_t=2$. The order of the transition is systematically examined using
finite-size scaling methods. Behavior of the interface tension and the latent
heat for an increasing Higgs boson mass is also investigated. Our results
suggest that the first-order transition terminates around $M_H \sim 80$GeV.
