The present invention provides a resin sealing device and a resin sealing method. The resin sealing device includes a substrate conveying mechanism including a claw portion that is movable in a vertical direction and a horizontal direction and a substrate holding portion capable of holding a substrate mounted on the claw portion, and a forming mold that includes an upper mold and a lower portion A mold, and a support portion, the mold cavity being formed in at least one of the upper mold and the lower mold, the substrate held by the claw portion being insertable together with the claw portion in a horizontal direction between the upper mold and the lower mold Molds which support the said board | substrate when the said nail | claw part is pulled out from between the said upper mold | type and the said lower mold | type in a horizontal direction, The mold clamping mechanism which clamps the said board | substrate in the said The upper mold and the lower mold are clamped together in a state in which the upper mold and the lower mold are clamped, thereby resin-sealing the substrate in the cavity.