Informal sector workers are workers whose doing on their own job and use their physical strength to do their works. Mostly, informal sector are unskilled labour and having not enough education to work at the big company or in the formal sector. Informal sector is the largest sector in Indonesia, they have different needs from the formal sector workers. The formal sector workers have a specific protection which is regulated by law, in contrast the law seems not cover the informal sector for protection and job security. This research have a purpose to understand the arrangement by the law and government regulation on the guarantee of legal protection against the informal sector workers, particularly about the job security and protection for the construction workers. Construction workers are workers who become part of the informal sector and together having an interest in national development. To do their job in construction work, they often use heavy equipment and technology with a big risk. They easily suffering many difficulties and accidents, that they need law protection as a worker. Workers are people who works and get salary, so then, the construction workers are also part of the workers just as the formal sector that need to be protected by law.