Idiopathic pulmonary fibrosis (IPF) is a disease of unknown etiology which accounts for a large proportion of cases of idiopathic interstitial pneumonia. It has a very poor prognosis with a 5-year survival rate of 30% or below, and so far there has been no guideline in Japan offering an established effective therapy based on evidence. In addition to the establishment of basic therapies, there is also an urgent need to establish therapies to deal with complications, as death occurs in many cases due to acute exacerbation or comorbid lung cancer. It was therefore decided to formulate a guideline in order to promote evidence-based clinical practice, to further improve the quality of medical treatment in the clinical setting, and to allow the benefits to be enjoyed by the public.