The invention belongs to the technical field of firecrackers and provides a built-in firecracker so as to solve the problems of low recycling rate, low safety coefficient and the like of existing built-in safe and environment-friendly firecrackers. A built-in firecracker single body comprises a lead, an inner container made of toughened plastic and a jacket; the inner container adopts a cylindrical structure; a partition integrated with the cylindrical structure is arranged in the cylindrical structure and divides the inside of the inner container into an upper cavity and a lower cavity; the upper cavity contains an explosive; the lower cavity contains a solid lead filling agent; a lead hole is formed in the partition; the lead is led out of the inner container through the lead hole and the lower cavity from the explosive and is finally led out of the jacket; and a sealing layer is arranged at the end of the upper cavity. The firecracker is integrally molded, is made of the toughened plastic and is free of damage and capable of being recycled after being fired. The firecracker is simple in structure, the structure of an injection mold of the firecracker is simplified, the manufacturing technology is simplified, and the production cost is reduced. The safety is greatly improved, and casualties cannot be caused easily.