Multiple-direction vibration widely exists in the environment, which is harmful to instruments and people. Hence, the high demand for vibration isolators with exceptional efficiency is thus evident. Although the proposed nonlinear energy sink was proven to be highly utility, most of the developed such devices, even with some inerter enhanced NESs, are limited to one-dimensional vibration suppression. In this paper, we propose a two-dimensional inerter-enhanced NES (2D IE-NES) which is applicable for multiple-directional low-frequency vibration suppression. The Lagrangian method is employed to derive the dynamic equations of the 2D IE-NES. Then these differential equations are solved by means of the Runge-Kutta method. Numerical results show that the novel 2D IE-NES configuration can isolate vibration more efficiently than the traditional NES under both instantaneous shock and constant periodic excitation. The role of the inerter in the vibration decaying process is highlighted in energy flow. This paper provides a new platform for the low-frequency multiple-direction vibration isolator.