A neck-mounted diffuser set comprises a diffuser and a neck-mounted diffuser. The neck-mounted diffuser device comprises a neck-mounted body and at least one receiving unit. The diffuser is adapted to adhere to a volatile liquid. The neck body has a neck rear section and two neck side sections respectively connected to opposite ends of the neck rear section. The at least one receiving unit is formed on one of the two neck side sections and includes a receiving groove and an erosion resistant layer. The accommodating groove is formed in the two-neck side section and is adapted to be provided for the diffuser. The anti-erosion layer is located in the accommodating groove for isolating the diffuser member to a groove wall surface defining the accommodating groove, and is resistant to the erosion of the liquid adhered by the diffuser.一種頸掛式擴香套組包含一擴香件及一頸掛式擴香裝置。該頸掛式擴香裝置包括一頸掛本體及至少一容置單元。該擴香件適於沾附一個具有揮發性的液體。該頸掛本體具有一頸後段及兩分別連接於該頸後段的兩相反端的頸側段。該至少一容置單元形成於該兩頸側段其中一者，並包括一容置槽及一抗侵蝕層。該容置槽形成於該兩頸側段其中該者，並適用於供該擴香件設置。該抗侵蝕層位於該容置槽，用以將該擴香件隔離於一界定出該容置槽的槽壁面，並能抵抗擴香件所沾附的該液體之侵蝕。
