To provide a ventilation type rotary drying device for garbage that can be operated continuously for a long time where throughput per volume is large, structure in a shell is simple, vinyl in garbage is less deposited, and paper is less ignited.

In a ventilation type rotary drying device 1 where a main pipe 5 for hot air is inserted into a shell 2 that is rotated and driven, a number of branch pipes 11 are branched from the main pipe 5, and hot air is blown to a tarminar flow with a crescent-shaped cross section that is formed by garbage passing the inside of the shell 2 from the branch pipe 11, the branch pipe 11 is set to a length where a space remains between the tip and the tarminar flow surface. Then, the main pipe 5 and the branch pipe 11 are packaged by a heat-insulating material 12.