To provide a plasma ignition device capable of preventing misfire caused by difference in timing between fuel injection and plasma generation.

The plasma ignition device 1 is equipped with an ignition plug 10, a power supply 21, an ignition coil 23, a discharge power supply circuit 20 equipped with an ignition coil drive circuit 24 which is controlled for open and close by an electronic control device 25 and controls the drive of the ignition coil 23, and a high voltage power supply comprising a plasma generation power supply circuit 30 which is equipped with a plasma generation capacitor 33 charged by the power supply 31, makes gas in a discharge space 140 a plasma state by application of breakdown voltage Vsc and supply of plasma generation current Ipl and performs ignition of an internal combustion engine 40. After the plasma generation current Ipl decreases to 10 mA or less, a period in which a discharge current Idc is 20 mA or more and the breakdown voltage Vsc is 100 V or more is continued for 600 sec or more.