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We present a simple and facile method for producing high-performance hydrogen (H₂) sensors based on vertically ordered metal-oxide nanorods with a Pd films on a 4-inch SiO₂/Si substrate by a glancing-angle deposition. Firstly, optimal density of nanorods was formed by changing an incident angle of vapor flux. Secondly, nanogaps between each nanorod were precisely controlled by manipulating thickness of Pd films. At room temperature in ambient air, 15-nm-thick Pd-coated SiO₂ nanorods showed the rapid on-off switches. The average response time was approximately 2.8 s (the longest response time: 5 s), and the recovery time was less than 1 s for 2%–0.8% H₂. For 20-nm-thick Pd-coated SiO₂ nanorods, detection of limit was reduced to 10 ppm due to semi-on-off operation. The reproducibility of our approaches was investigated by fabricating the Pd-coated SnO₂ nanorods. They also exhibited the high H …