In a hair dryer with a brush emitting minus ion to a hair in brushing, effect of the minus ion for hair treatment is increased. The hair dryer is comprised of a main body and a brush unit detachably engaged with an air outlet of the main body. A plurality of ion outlets is provided on a housing of the main body and disposed outside of the air outlet so that minus ion is emitted toward the brush unit. Since the minus ion emitted from the ion outlet is not shielded by the hair in brushing, the minus ion can be sprayed widely to the hair, and not directly heated by hot air flow blowing from the brush unit.