The degree of conversion(DC) of composite resins are closely correlated with the mechanical properties. Fourier Transform Infrared(FTIR) Analysis is currently used to determine the DC for many advantages. In this study, three composite resins; Aelitefil(AF; U.S.A), VeridonFil-Photo(VF; Korea), Z-100(ZH; U.S.A) and two compomers; Compoglass(CG; Lichtenstein), Dyract(DR; Germany) were used to make specimens with thickness of 0.1±0.02㎜. After one group of samples were light-cured for 20 second and those of the other group were Argen laser-cured with 0.23W continuous mode for 5 second, all the samples were kept dry at 37℃ for 24h. From the spectra acquired on an FTIR spectrometer(Bruker IFS 88, Germany), the aliphatic C=C absorbance peak at 1640㎝-1 and the N-H reference peak at 3380㎝ -1 were measured using a standard baseline technique. The ratios of absorbance of C=C/N-H before polymerization to that of C=C/N-H after polymerization were used to calculate the residual C=C bonds. The results were as follows ; 1. The descending order of the degree of conversion was VF > AF > ZH > CG > DR in light cured group(p<0.05). 2. The descending order of the degree of conversion was VF > AF > CG > ZH > DR in laser cured group(p<0.05). 3. The degree of conversion of light-cured group was higher than laser-cured one only in ZH and not significantly different in other materials(p<0.05). In conclusion, the argon laser showed efficient curing capacity compared with light curing unit except ZH and the degree of conversion of compomer was inclined to be lower than that of composite resin.