A faucet device configured to release or shut off hot water supplied from a hot-water supply source, or cold water supplied from a cold-water supply source, or a mixture thereof, the faucet device comprising: a base member for being fixed to an installation surface; an outer shell member including a columnar section attached to the base member; a casing member inserted into the columnar section of the outer shell member and having one end fixed to the base member; a hot-water supply channel and a cold-water supply channel provided inside the casing member and extending downstream from the base member; a single lever cartridge provided inside the casing member and including an on-off valve for adjusting a mixture ratio and flow of the hot-and-cold water mixture, and a single lever for opening and closing the on-off valve; a connecting member (50, 52) provided inside the casing member and connecting downstream ends of the hot-water supply channel and the cold-water supply channel to the single lever cartridge; and a cartridge holding member that fixes the single lever cartridge to the connecting member (50, 52), the casing member has first mechanical engagement means (60, 72b) for retaining the connecting member (50, 52) in accordance with mechanical engagement,the hot-water supply channel and the cold-water supply channel are formed of supply pipes (44, 46) separate from the base member, characterized in that the casing member is formed of a metallic plate or pipe, the supply pipes include connection sections (44a, 44b, 46a, 46b) connected in a watertight manner by being fitted into connection receivers (16c, 16d, 50c, 50d) of the base member and the connecting member (50, 52), and the connection receivers (16c, 16d, 50c, 50d) of the base member and the connecting member (50, 52) have clearances (d1, d2, d3, d4) that allow the connection sections (44a, 44b, 46a, 46b) of the supply pipes (44, 46) to move while maintaining watertight connection relative to the connection receivers (16c, 16d, 50c, 50d) of the base member and the connecting member (50, 52). a base member for being fixed to an installation surface; an outer shell member including a columnar section attached to the base member; a casing member inserted into the columnar section of the outer shell member and having one end fixed to the base member; a hot-water supply channel and a cold-water supply channel provided inside the casing member and extending downstream from the base member; a single lever cartridge provided inside the casing member and including an on-off valve for adjusting a mixture ratio and flow of the hot-and-cold water mixture, and a single lever for opening and closing the on-off valve; a connecting member (50, 52) provided inside the casing member and connecting downstream ends of the hot-water supply channel and the cold-water supply channel to the single lever cartridge; and a cartridge holding member that fixes the single lever cartridge to the connecting member (50, 52), the casing member has first mechanical engagement means (60, 72b) for retaining the connecting member (50, 52) in accordance with mechanical engagement,the hot-water supply channel and the cold-water supply channel are formed of supply pipes (44, 46) separate from the base member, characterized in that the casing member is formed of a metallic plate or pipe, the supply pipes include connection sections (44a, 44b, 46a, 46b) connected in a watertight manner by being fitted into connection receivers (16c, 16d, 50c, 50d) of the base member and the connecting member (50, 52), and the connection receivers (16c, 16d, 50c, 50d) of the base member and the connecting member (50, 52) have clearances (d1, d2, d3, d4) that allow the connection sections (44a, 44b, 46a, 46b) of the supply pipes (44, 46) to move while maintaining watertight connection relative to the connection receivers (16c, 16d, 50c, 50d) of the base member and the connecting member (50, 52).