Cancer is one of the main disease to threat for human health. Besides surgery and medical treatment (chemotherapy), radiotherapy is commonly used treatment method to kill cancer cell. For this method high energy photon is required. Clinic Lineer Accelerator (cLINAC) relatively lower energy than other LINAC has been used to obtain photon via bremsstrahlung processes. When accelerated electron beam impinges to the thin target bremsstrahlung occurs and photon can be created. Those photons can be focused on cancer cell and kill cancer. In order to focus photon beam collimator materials in LINAC head generally contains heavy elements is used and the interaction of bremsstrahlung photon with the such heavy nuclei the neutron can be produced inside the treatment rooms. The threshold of the neutron production for those materals is about 10 MeV. As the neutron is more dangerous than photon it is important to determine neutron dose during radiotherapy treatment. In this study neutron dose rate has been measured and simulated in radiotherapy room.