A pulse rocket motor has a hollow cylinder-like first grain situated in a rear section of a pressure vessel; a first igniter for igniting the first grain; a hollow cylinder-like second grain situated in a front section of the pressure vessel; a second igniter for igniting the second grain; and a dividing sheet member that covers the second grain within the pressure vessel. The dividing sheet member includes a dividing sheet expanding at least along the inner circumferential surface of the second grain and holders formed integrally with the dividing sheet at both ends of the dividing sheet by cure adhesion and attached to the pressure vessel. The dividing sheet includes a brittle portion that expands along the inner circumferential surface of the second grain through a rear end face of the second grain and is more brittle than other portions.
