Provided is a packaged hydrogen-generating agent, the hydrogen-generating reaction of which is highly stable and repeatable, and which preferably is resistant to influence from changes in the environmental temperature. Also provided are a method for manufacturing said package, and a hydrogen generation method. The packaged hydrogen-generating agent is provided with: a hydrogen-generating agent (1); a covering material (2) which encloses the hydrogen-generating agent (1) and allows deformation; and a water-absorbing body (3), part of which is in contact with the hydrogen-generating agent (1). The covering material (2) preferably covers at least the area around the contact part (3a) where the water-absorbing body (3) and the hydrogen-generating agent (1) are in contact, so as to create a firm attachment at the contact part (3a).