In application of a green-house effect, under such a concept as to collect solar energy passively into the house and to exhaust moist air passively from the house, an all weather passive-type solar Ogako drying house H which is available for all day through a year was made up improving an agricultural vinyl-house in which Ogako is dried continuously during carriage on the belt conveyors 4, 5 due to solar energy and auxiliary heat, and then moist air yielded when drying Ogako is exhausted through an insulated cylinder 13. In this case, Ogako means sawdust or tipped small particles of wood which is raw material in order to produce a woody pellet fuel.