  We propose a scheme for generating a genuine $\chi$-type four-particle
entangled state of superconducting artificial atoms with broken symmetry by
using one-dimensional transmission line resonator as a data bus. The
$\Delta$-type three-level artificial atom we use in the scheme is different
from natural atom and has cyclic transitions. After suitable interaction time
and simple operations, the desired entangled state can be obtained. Since
artificial atomic excited states and photonic states are adiabatically
eliminated, our scheme is robust against the spontaneous emissions of
artificial atoms and the decays of transmission line resonator.
