The quantum characteristics of the single walled carbon nanotube (SWCNT) quantum dot device are investigated under the effect of an external strain. This device is modeled as single walled carbon nanotube quantum dot connected to metallic leads. These two metallic leads operate as a source and a drain. The conducting substance is the gate electrode in this three-terminal device. Another metallic gate is used to govern the electrostatics and the switching of the carbon nanotube channel. The substances at the carbon nanotube quantum dot/ metal contact are controlled by the back gate. The electric current is deduced using Landauer-Buttiker formula. Numerical calculations are performed for armchair SWCNT and zigzag SWCNT and the obtained results show that both energy gap and the current are chiral dependent. So, results show that due to the effect of strain, the quantum transport characteristics of the present device are changed. Periodic oscillatory behavior of the current for both types of SWCNTs might be due Coulomb oscillation and the THz-photon assisted tunneling (PAT) of an electron in the SWCNT QD to the drain electrode. The present research is very important in the field of nanoelectronics devices and nanoelectromechanical system resonators.