For an enterprise to survive in extremely competitive world, it had better to down budget and resource of unimportant fields so that the enterprise can concentrate resources on the strong field. Nowadays in Korea, it is important to research outsourcing for strengthen the competitive power in apparel maker because of recent depression. The questionnaire was composed of 14 factors about outsourcing effect. The questionnaires were selected for finial analysis 67 apparel makers in Pusan and Seoul and data was analysed by using paired t-test by SPSS program. Almost of apparel makers (85.07%) has been outsourced the sewing process to contractor or vendor. Outsourcing in this case is marked lower effect than insourcing except reducing cost, economy of time and overcoming internal resources. This means that our outsourcing has been progressed with so many risk. If we have research the successful outsourcing and have a strategic vision and plan with vendor and product mutually beneficial relationship, we can share the risk and creating new business synergies through outsourcing.