In this paper, a numerical investigation of steady laminar natural convection in a square enclosure, contain a concentric heated rod and a bundle of four triangular heated cylinders was carried out. Two cases of enclosure inclination angle were studied: case (I) at φ=0o and case (II) at φ=45o. Air is filled the enclosure, and the inner heated cylinders are located at equal distance (E) from the enclosure center. A finite element software package (FLEXPDE) is used in the present study to solve the set of non-linear equations governing the process. Solutions are obtained for aspect ratio h/H=0.29, a values of distance E=0.27-0.44 and a range of Rayleigh number 103≤ Ra ≤ 105. The effect of Ra, E and φ were examined. Results are presented by streamlines, isotherms and Nusselt number and they indicates that the Nusselt number is significantly increases with increasing Ra, E and φ. A comparison of the streamlines, isotherms and mean Nusselt number was made with that obtained by other authors, which it reveals a good agreement.