A drive transmission mechanism for transmitting torque between two or more rotary shafts in synchronization with one another without need for lubrication thereby eliminating occurrence of oil contamination, and an oil-free fluid machine equipped with the mechanism, are provided. A magnetic drive disk 16 and a synchronization gear 18 are attached to a rotary shaft 14 connected to a drive motor 11, a magnetic drive disk 17 and a synchronization gear 19 is attached to a rotary shaft 15, torque transmission from the rotary shaft 14 to the rotary shaft 15 is carried out in two ways, via the magnetic drive disks 16, 17 and via the synchronization gears 18, 19, and at least one of the synchronization gears is made of plastic material. With the construction, torque transmit load between the rotary shafts via the synchronization gears is decreased, and a plastic gear or gears can be adopted for synchronization gears without reducing life of the gears without need for lubrication oil.