We observed an anomalously outbursting state of SU UMa which occurred in 1992 .
Time-resolved photometry revealed the presence of signals with a period of 0.0832 \pm 0.0019 d , which is 3.6 \sigma longer than the orbital period ( 0.07635 d ) of this system .
We attributed this signal to superhumps , based on its deviation from the orbital period and its characteristic profile .
During this anomalous state of SU UMa , normal outbursts were almost suppressed , in spite of relatively regular occurrences of superoutbursts .
We consider that an ensuing tidally unstable state following the preceding superoutburst can be a viable mechanism to effectively suppress normal outbursts , resulting in an anomalously outbursting state .