Abstract H(D) atoms terminating Si(001) and Si(111) surfaces were detected directly by elastic recoil analysis of medium-energy ion scattering (MEIS). Appropriate selection of the incident He + energy and the recoil angle allows direct detection of recoiled H +(D +) and H −(D −) ions by an electrostatic analyzer (ESA) without the need for absorber foils and additional techniques such as the time-of-flight method. We designed and fabricated a new toroidal ESA with a wide interelectrode distance of 18 mm, which covers a broad energy range at a constant applied voltage, and realized good statistics. The present new method was applied to analysis of Si(001) and Si(111) surfaces terminated with H(D) by different chemical treatments. The H(D)-terminated Si(001) surfaces were prepared by the RCA cleaning process followed by dipping into a HF+H 2O(D 2O) solution, while the H-terminated Si(111) surfaces were formed using a HF–NH 4F buffer solution. Analysis revealed that (i) the ratio of the amount of D to that of H on Si(001) coincided with the D/H mixing ratio of the HF(48%)+D 2O solution, and (ii) the amount of H on the Si(001) surface treated with the HF+H 2O solution was 2.1±0.3 times larger than that of H on Si(111).