PROBLEM TO BE SOLVED: To provide a volatilization vessel which is capable of easily executing the operation from a sealed state to a usable state of a vessel body before the use in a very easy manner compared with a conventional one, and reliably and easily forming an outside air introducing passage for communicating with the inside and the outside of a vessel body after the unsealing, and extremely convenient after the unsealing.SOLUTION: The volatilization vessel comprises a vessel body B which is accommodated in a case body A with its upper end being opened and with a liquid suction wick D being hanged and fixed therein, a cap E which is attached to the vessel body B and provided with a press-breakable, easily-cuttable part 41a on its top part, a case lid F which can be fitted with a different depth at the horizontally turning position at the predetermined angle with respect to the case body A, and a volatilization plate G which is pierced in and fixed to a lid fixing part 54. The liquid suction wick D and the volatilization plate G communicat with each other when the case lid F is fitted from the shallow fitting position to the deep fitting position in a horizontally turning state at the predetermined angle to open an outside air introducing passage for communicating with the inside and the outside of the vessel body B through a cut-through portion of the easily-cuttable part 41a.
