We performed ⁷⁵As-NMR measurements to investigate the normal-state magnetic properties of CeRh₂As₂, a recently-discovered heavy-fermion superconductor. The magnitude and temperature dependence of the Knight shift at the As(2) site indicate easy-plane-type magnetic anisotropy in CeRh₂As₂. With regard to spin fluctuations, the temperature dependence of the nuclear spin-lattice relaxation rate 1/T₁ arising from the 4 f electrons decreases from high-temperature constant behavior on cooling at ∼40 K, which is a typical behavior of heavy-fermion systems. In addition, 1/T₁ becomes constant at low temperatures, suggesting spatially two-dimensional antiferromagnetic fluctuations.