Although recent discussions have been progressing, the informatization level of small and medium-sized enterprises (SMEs) had been recognized merely as being relatively inferior compared to large enterprises, with systematically rigorous analytical methods and studies demonstrating the effects of improving informatization levels remaining minimal. This study measured the informatization level of SMEs comprehensively through a systematic methodology based on a field survey, compared this with large enterprises to reassess the realistic position of SMEs, and examined the relationship between the derived informatization level and SME performance indicators, thereby demonstrating the validity of investment in SME informatization. The results showed that while SMEs' informatization level is indeed inferior to that of large enterprises, their willingness to pursue informatization and awareness of its necessity far exceeds that of large enterprises, leading to the conclusion that if additional support is provided through policy measures, SME competitiveness can be raised above a certain level through informatization. Regarding the effects of informatization, how the established information systems are utilized was found to have the greatest impact on business performance, and it was demonstrated that informatization brings significant benefits not only in terms of sales revenue but also in enhancing the organizational capacity to respond more proactively and flexibly to future business environments. At a time when the share of SMEs in the economy is growing daily, this study shows that greater efforts must be made to improve informatization levels for the recovery of SME competitiveness, which contributes significantly to national competitiveness.