A solid state disk is provided, including: a main body, a light-emitting module and a light-guiding portion. The main body includes a shell portion, a substrate disposed in the shell portion and a memory module disposed on the substrate. The substrate further has a transmit port electrically connected with the memory module. The light-emitting module has a board disposed on the main body and a light-emitting portion disposed on the board. The light-guiding portion is disposed corresponding to the light-emitting portion. At least partial light from the light-emitting portion is transmitted outside the solid state disk through the light-guiding portion.