[Problem] To provide: an inorganic solid material which can exhibit hydrogen sulfide slow-release performance at ambient temperature in the atmosphere and can be handled safely; a method for producing the inorganic solid material; and a hydrogen sulfide generation method using the material. [Solution] A layered double hydroxide having HS- and/or Sk 2- (wherein k represents a positive integer) intercalated between layers thereof (i.e., a sulfide ion-containing LDH) is produced, and the sulfide ion-containing LDH is air-tightly packaged in a packaging material to form a packaged body and is stored in the form of the packaged body. For the generation of hydrogen sulfide, the packaging material in the packaged body is taken off to expose the sulfide ion-containing LDH in the atmosphere, so that hydrogen sulfide can be released slowly.