The present invention provides a method for manufacturing a sealed cell, capable of reducing labor and time for managing members of an insulated member and a down-lead body, preventing the down-lead body from contacting with an inner surface of a cell tank, and thinning the cell. An insertion throughhole (27) of the down-lead body (13) is cooperated in a matching pin (39) of a mold (35), the down-lead body is embedded between a pair of holding pins (41, 41) of the mold, and the down-lead body is mounted in an inner space of the mold. Then, a melting resin is injected into the inner space of the mold, such that the insulated member (11) covers the front and the back, the left and the right and the top of the down-lead body, such that the insulated member is integrated and formed on the down-lead body. Moreover, a negative terminal (12) is inserted in the throughhole (25) crossing a cover (3) in a mode of the intervention of the sealing member (10), the lower end part of the negative terminal is mounted with the down-lead body together with the insulated member, and the lower side of the down-lead body is connected with a cathode collector down-lead (9) extending from an electrode body (2).