Risk information may be one of the most important factor for worker's safe behavior because that safe behavior can be oriented by attitude based on risk information. Traditionally KAP(knowledge, attitude and practice) model was useful frame for the change of human behavior. Knowledge is formed by information through experience and education. Worker's health may be prevented by his or her own active safe behavior based on risk information. This paper is to investigate the effect of labor union on the provirion of risk information by labor union. Data for analysis is the third Korean Working Conditions Survey done by Occupational Safety and Health Research Institute in 2011. The sample size is 50,032 economic active person surveyed by household interview survey with structure questionnaire by trained interviewer. The difference of risk information provision among employees was tested by mean difference test. The level of risk information of employees of companies with labor union is higher than that with non labour union. This paper has some implication for the promotion of safe behavior of employees through risk information provision mediated by labor union. Some limitation of this study may be considered because of using the cross sectional survey data.