To provide a curtain device having a cloth slat, having an extending function by moderately connecting cloth slats, keeping the operative cloth slats in the flat state, and easily assembling and disassembling the cloth slats.

This curtain device includes: a head rail 11, a bottom rail 12 positioned below the head rail 11, a number of cloth slats 14 provided in parallel between the head rail 11 and the bottom rail 12, some positioning cords 13 connected to the head rail 11 and the bottom rail 12, and located at two side edges of the cloth slats 14, and the cloth slat for positioning the cloth slats at designated spaces between the head rail 11 and the bottom rail 12.