Cancer is one of the main death causes among health issues worldwide. There are approximately reported around 8.2 million victims in 2012. Early treatment and prevention should be conducted to reduce the high mortality. Cancer detection is necessary as an early warning system to properly treat detected cancers. Cancer imaging as one of various cancer detection techniques has become more reliable for cancer detection. This technique has been developed by using a wide spectrum of electromagnetic from microwave into optics. Terahertz (THz) imaging systems have also been developed to provide cancer imaging systems. The use of this spectrum, which is also known as a gap region between electronics and optics domain, has specific advantages for cancer detection systems, such as low radiation power and cancer transmission or reflection fingerprints located in this spectrum region. Among various cancers, breast cancer is the most common cancer suffered by women. In this paper, simulation of THz imaging is conducted by using microstrip linear array antennas for breast cancer detection. The antennas as transmitter and receiver of the THz waves are separated for a distance of 4.5mm. An object, including the breast cancer, is modelled by considering three layers of tissue with different values of permittivity, i.e. fat (ϵ
= 2.41), fibrous (ϵ
= 2.8), and tumor (ϵ
= 3.15). The THz imaging is simulated at frequencies of 0.302 THz, 0.312 THz, and 0.322 THz. Simulation is conducted by using CST Microwave Studio. The simulation results show that the cancer tissue can be detected by considering and analyzing the transmitted waves detected by the receiver antenna. THz imaging at a frequency of 0.312 THz gives the clearest imaging, which could affected by the antenna resonance. These results indicate that the THz imaging technique has potentials to be applied for cancer early detection.