Controlling the electrical property of single-walled carbon nanotube (SWCNT)-based devices is challenging because the SWCNTs have semiconducting or metallic characteristics that are dependent on their chirality. In this report, we demonstrate that a monolayer SWCNT bundle Langmuir-Blodgett (LB) film exhibits anisotropic electrical properties owing to the aligned assembly, and therefore the devices fabricated from this film demonstrate different gating effects reliant on the channel dimensions. Control of the channel dimension significantly affects the modulation of semiconducting behavior of the SWCNT-based devices. The shrinkage of the channel dimension induces a drastic decrease in the metallic pathway, which in turn enhances the semi-conducting behavior of the device.