<p>We experimentally and numerically investigate an aluminum (Al) chiral metasurface exhibiting broadband reflective circular dichroism (RCD) in the visible. The metasurface comprises a Z-shaped unit cell patterned in electron-beam resist on fused silica and covered with thermally evaporated Al. A lift-off-free “double-layer” Al/resist architecture is formed in a single deposition, consisting of (i) Al on the resist surface and (ii) Al at the aperture bottoms, separated by the resist. Rigorous coupled-wave analysis (RCWA) reproduces the measured co- and cross-polarized reflectances under right- and left-circularly polarized illumination and clarifies parameter dependences. The simulated RCD, defined as the difference between cross-polarized reflectances for the two circular polarizations, exceeds 0.2 over a visible band (≈480–630 nm). The measured spectra show consistent peak positions, with a maximum RCD of ~ 0.12 and values ≥ 0.05 across ~ 508–640 nm. The remaining simulation–experiment gap is likely influenced by uncertainties in thickness, particularly the postexposure/development resist thickness (estimated to decrease from ~ 100 nm to ~ 50–60 nm), as well as metallization-related factors such as the effective Al coverage/thickness. Electromagnetic-field analysis indicates polarization-dependent localization: edge-localized plasmons enhance the magnetic response and cross-polarized reflection for one handedness, whereas field confinement inside the recesses increases absorption and suppresses the cross-polarized response of the opposite handedness. Because the structure is implemented without multilayer alignment and relies on a single metal deposition, it provides a fabrication-friendly route to visible-band chiroptical devices. This lithography-compatible, visible-band platform is promising for polarization control and chiroptical sensing, including compact components compatible with white-light illumination.</p>