A high-voltage discharge lamp lighting apparatus has a stabilizer 12 which supplies a power voltage used for maintaining the lighting operation to a high-voltage discharge lamp 20, and an ignitor circuit having an oscillating circuit-for-driving 13 in which a start pulse generates upon starting the lighting operation of the high-voltage discharge lamp, and high-voltage pulse generating transformers (14a, 14b, and 14c) which increase a voltage of the start pulse. Further, the high-voltage discharge lamp lighting apparatus includes a cap portion 16 to which the high-voltage discharge lamp 20 is attached and held, including a part of the high-voltage pulse generating transformers of the ignitor circuit, and a socket portion 11 to which the cap portion 16 is attached and is fit, including at least the oscillating circuit-for-driving 13 in the ignitor circuit and a portion of the high-voltage pulse generating transformers except for a part included in the cap portion 16. A primary coil 14a, a secondary coil 14b, and a magnetic coil 14c of the high-voltage pulse generating transformers are dividedly accommodated and arranged in the cap portion 16 and the socket portion 11. Thus, the continuous generation of a high voltage is prevented at connecting pieces of the portions upon detaching the cap portion 16 from the socket portion 11, the electric shock of an operator is prevented, and costs are reduced upon replacing the lamp.