Time series PALSAR-2/ScanSAR data and Landsat data were used for examining the differences in detection timing of deforestation. Optical sensor-based (Landsat) deforestation information taken about every 16 days and SAR data taken about every 1.5 months were used, and the temporal change of L-band γ⁰ was examined for the deforestation areas. The γ⁰_HH value increased by 1.2 dB on average for areas undergoing the early stages of deforestation, where fallen trees were left on the ground. The detection timing was almost same as that using the optical sensor. On the other hand, the γ⁰_HV value decreased by 1.2 dB on average for areas undergoing the late stages of deforestation, where fallen trees were removed. The detection timing using γ⁰_HV was about a few month after the detection using γ⁰_HH, or optical sensor. It is concluded that γ⁰_HH is useful for early-stage deforestation detection, and γ⁰_HV is useful for late-stage deforestation detection.