SPARK PLUG AND PLASMA GENERATING DEVICE

To provide a spark plug that can reduce power loss and prevent erosion of a tip end part of a central electrode, even in a configuration such that a discharge current and an electromagnetic wave are emitted from a terminal fitting part of the spark plug, and a plasma generation device using the spark plug. The spark plug is provided with a central electrode 2 including a terminal fitting part 2A and an electrode main body 2B electrically connected to the terminal fitting part 2A, an insulator 3 formed with an axial hole 30, which the central electrode 2 is fitted into, a main fitting 4 that surrounds the insulator 3, and a ground electrode 5 that extends from an end surface of the main fitting 4 and is adapted to form a discharge gap that causes a spark discharge between the central electrode 2 and the electrode main body 2B. The electrode main body 2B is constituted of a front electrode 25 including an electrode tip part 25a for causing the spark discharge with the ground electrode 5, a front dielectric cylinder 24 in a tube-like shape that covers the electrode tip part 25a, and a coupling conductive cylinder 23 in a tube-like shape that joins the front dielectric cylinder 24 and the terminal fitting part 2A.