Injuu Kyoushi

A private detective is told to investigate the accidental death of a girl in an all girl school. As a charming male teacher in a girls' school, he is soon chase after by a few girls, including his old neighbor girl who is no longer boyish looking. As he investigates, he gets friendly with the girls(refuse and bye bye). An evil spirit roaming around and messing with some girls doesn't make his job any easier, but he has help from his Ghost Sweeper friend. Anyway, if he enjoys his days, he will be fine and happy with his girl later.

[From Li's Fun House]