We analyzed the loop-top source of an X 1.2 flare, which occurred on
1998 April 23, based on the hard X-ray and the microwave data. This
flare occurred slightly behind the solar limb. Therefore, the footpoint
emission, which is normally dominant, was blocked and only the source
located at the loop-top region is well observed. The hard X-ray emission
from the loop-top source is revealed to come from both the nonthermal
electrons and the thermal plasma. The power-law index of the
nonthermal electrons observed in hard X-rays is about 2.9
on the assumption of the thin-target model. This is consistent with the
index of 2.5 - 3 derived from the dual-frequency observation in
microwaves. This is the evidence that the nonthermal
high-energy electrons exist in the loop-top region.
