It is sought to provide a negative ion generator, which can suppress positive ion generation, permits ready control of the quantity of generated negative ions and permits its size and thickness reduction. The negative ion generator 1 is of electron emission type in which, for negative ion generation, electrons are emitted into air by impressing a negative high voltage on a stylus electric discharge electrode 6. A piezoelectric transformer 5 is used for amplifying a non-rectified drive voltage from a transformer drive circuit 9. As a result of rectification of the AC high voltage from the piezoelectric transformer 5, a negative high voltage is obtained, which is impressed on the stylus electric discharge electrode 6 for electron emission wherefrom, thereby generating negative ions in air.