Patent ID: 7064488

Claim:
A compact self-ballasted fluorescent lamp, comprising: an arc tube formed by a glass tube double-spirally wound from a middle to both ends thereof around a predetermined axis; and a cylindrical holding member having an end wall on which a pair of tube-holding structures are provided for holding the arc tube in a state where both end parts of the glass tube are inserted in and held by the tube-holding structures, wherein a pitch of (a) each end part and (b) an adjacent spiral part in a direction of the axis is larger than a pitch of other adjacent spiral parts, to widen a gap between each end part and the adjacent spiral part, and a distance between (a) a first point that is at a middle of an area sandwiched between the pair of tube-holding structures in a circumferential direction of the end wall as viewed in the direction of the axis and (b) a second point that is on an outer surface of a spiral part positioned outward with respect to the holding member and facing the first point, is in a range of 1.5 to 4.0 mm inclusive.