PROBLEM TO BE SOLVED: To significantly reduce or prevent the forming of an exudative mercurous and mercuric compounds due to oxidization of an element state mercury by introducing an inorganic or an organic antioxidant into a fluorescent or low-pressure mercury arc lamp. SOLUTION: When an antioxidant is introduced into a lamp structure or toxic exudative characteristics method testing solution, an ion or copper metal part is prevented from being oxidized to an oxidization form being soluble and having oxidization capability to a soluble oxidization mercury of an element state mercury. Therefore, production and dissolution of a soluble ferric and a cuprous compounds from a lamp part is decreased or prevented, and as a result, an exudative mercury compound is reduced and prevented. The antioxidant is selected from among groups consisting of an element-state iron, an ascorbic acid and an ascorbic acid sodium. Use of the ascorbic acid is preferable.