Based on compilation by Fan and Su (1998, AAA 70.158.417), the variability property is discussed for the Seyfert galaxy NGC 415 1 using the structure function, V(tau)(1/2) similar to tau(k). The derived k is 0.35 +/- 0.03, suggesting that the disk-instability favors the star-burst model as an explanation for the mechanism of the variability in this source.