The disclosed is a method for attaching a charging wire. At first, a first end of a charging wire is locked to a wire locking portion of a process frame, and portion of a torsion spring shaped wire electrode is engaged with a second end of the charging wire. Thereafter, a coil portion of the wire electrode is attached to a coil support portion of the process frame in a state in which a tension less than a set value is applied to the charging wire. Thereafter, a second spring leg portion of the wire electrode is moved to a fixed position fixed to an electrode support portion of the process frame in a direction in which a deformation amount of the wire electrode increases, without exceeding the fixed position in the first direction.