To provide an uncomplicated, practical and functional deceleration and transmission device in a rotary drier of squids and fish.

This uncomplicated, practical and functional deceleration and transmission device in the rotary drier of the squids and fish is obtained by installing a wheel comprising a belt-shaped plate in the lower part of a rotary drum body, fixing a motor by installing a motor base device, and constantly bringing a driving transmission roller of a motor shaft into contact with the inner side surface of the circumference of the wheel by pressure to rub them together to form the device for carrying out deceleration and rotary transmission by a dram. The device has a structure enabling the motor base device to be freely moved so as to make the rotary movement stable and to correspond to the rapid frictional force at the starting time.