A 72-year-old critically ill and intubated man was transferred to our hospital, because of worsening pneumonia unresponsive to Cefazolin and Meropenem, from the hospital where he had been admitted 8 days before to start maintenance hemodialysis for chronic renal failure but had fever from admission. In a few days his critical condition rapidly subsided with the initiation of Ciprofloxacin and his sputum culture on GVPC medium indicated Legionellosis, which was afterwards identified as L. longbeachae by PCR and DNA-DNA hybridization. After recovery he said that he had been fond of gardening and had been gardening immediately before the initial admission. Moreover, several reports from Australia suggested inhalation of aerosolized potting soil as the route of L. longbeacachae infection; therefore, we examined the soil of his home garden and identified it. Thus, we present this case as the first of L. longbeachae pneumonia in Japan, proved to be infected via inhalation of aerosolized home garden soil.