As companies began taking measures to cope with the changes in economic and industrial structures in Japan in 1980, the perspectives of workers varied and they began to pursue more flexible working styles. The temporary agency work system was prohibited at the time by Article 44; Labor Supply Business of the Employment Security Act.
However, for the purpose of accommodating the needs of companies that require temporary agency work when it is needed, and workers who wish to utilize their experience and skills, and choose the location, time, and type of job, the Worker Dispatching Act was established in 1985 and went into effect in 1986.

The important purpose of the Worker Dispatching Act is to "properly manage supply and demand in the labor market", and "achieve protection and stable employment of temporary agency workers".
As the economic and employment situations and labor policies in Japan have changed, and the needs of companies and workers have varied, amendments to the Act have been repeatedly discussed, and the regulations for types of jobs in which temporary agency workers are permitted to work, employment periods, and others have been revised over the years. Also, legislation ensuring "equal pay for equal work" for temporary agency workers has been passed and became effective since April 1, 2020. The chart below indicates the major amendments to the Act since its enforcement.