A rotary roller motor is disclosed herein. The rotary roller motor is a four-stroke internal combustion engine, wherein the rotor “rolls” around the inside of the engine block. The rotor is a two-part rotor having an inner part with a shaft and an offset circular lobe, and an outer rotor fit around the lobe. Two barriers are provided around the rotor chamber, a compression/power barrier and an exhaust/intake barrier. The combustion chamber has a non-reversing compression barrier and a compression hold barrier regulating the combustion of gas.