A new phase of ternary ruthenium oxide, Ba 2 Ru 7 O 18 , is discovered. The lattice parameters are: triclinic , a = 6.71(4) A, b = 7.10(4) A, c = 7.46(4) A, α= 93.2(2)°, β= 94.6(2)°, γ= 115.7(2)°. It has a Ba 2 Zn 7 F 18 -type structure composed of an egde-shared and corner-shared network of RuO 6 octahedra. The magnetic susceptibility around room temperature exhibits a Pauli paramagnetism with a relatively large value of χ=3.4×10 -4 emu/mol at 300 K, while it exhibits a large temperature dependence in the low temperature range without any evidence of magnetic phase transitions down to 2 K. The resistivity at 300 K is 1.1×10 -3 Ω cm, larger than that of normal metal. Unlike conventional metals, the resistivity exhibits T 1.2 -linear dependence in the low temperature region. These anomalous behaviors of magnetism and resistivity can be interpreted in terms of the non-Fermi liquid state.