DySc2N@C-80 is an endohedral metallofullerene showing single-molecule magnet (SMM) behavior. In this work, we encapsulated DySc2N@C80 SMMs into the internal one-dimensional nanospace of single-walled carbon nanotubes (SWCNTs). Using transmission electron microscopy, "peapod" structures were clearly observed. From magnetic field dependent measurements, DySc2N@C-80 showed stepwise hysteresis characteristic of SMMs even inside the SWCNTs, and the coercivity increased from 0.5 to 4 kOe. In addition, it showed slow relaxation of the magnetization without an applied external magnetic field. This system is the first example where SMMs have been encapsulated in SWCNTs, and this system could be used in future molecular-spintronics devices.