Sonobe was born in Ibaraki Prefecture on March 29, 1958. After graduating from Mito Commercial High School, he joined Japan Soccer League club Fujita Industries in 1976. The club won the league champions in 1977, 1979 and 1981. The club also won 1977 and 1979 Emperor's Cup. He retired in 1989. He played 173 games and scored 2 goals in the league. He was selected Best Eleven in 1978 and 1979.