An illuminant device includes at least an illuminant element and a lamp holder including a housing, a metal core printed circuit board (MCPCB) and a power-driving unit. The housing includes a first side and a second side opposite to the first side. The MCPCB is disposed on the first side of the housing and includes a base and a plurality of extending parts extended from the circumference of base in a bending forming manner and spaced from each other. The base has a plurality of holes, the extending parts are embedded within the housing, and the illuminant element is mounted on the base. The power-driving unit includes a circuit board, and a first end of the circuit board has a plurality of posts. The posts are respectively penetrated the holes and electrically connected to the MCPCB. In addition, a manufacturing method of the lamp holder is disclosed.