Patent ID: 7223145

Claim:
A manufacturing method of a fluorescent lamp, comprising: a hole opening step of opening holes, by melting with heat, each in an area in a vicinity of a first end of a first constituent tube and in an area in a vicinity of a second end of a second constituent tube, the first and second constituent tubes each having a U-shaped discharge path; a joining step of joining, after the hole opening step is performed, a first melted area formed around the hole in the first constituent tube with a second melted area formed around the hole in the second constituent tube; and a distance adjusting step of adjusting D 1 and D 2 so that D 2 /D 1 is within a range of 0.05 to 0.70 inclusive, where D 1 is a distance between the first melted area in the first constituent tube and the second melted area in the second constituent tube, and D 2 is a shortest distance, on a turning portion side of the fluorescent lamp, between the first constituent tube and the second constituent tube, the turning portion being where each U-shaped discharge path turns.