To provide a uniaxial eccentric screw pump having a simple and compact device configuration, and which enables a rotor to be rotated and revolved without a complicated operational control. A uniaxial eccentric screw pump (10) is equipped with a rotor drive mechanism (50) capable of causing a rotor (20) to rotate and to revolve. The rotor drive mechanism (50) has a rotation drive force transmission member (52) capable of rotating around a fixed central axis (C1), and a revolution orbit formation member (56) capable of causing the base shaft portion (54) of the rotor (20) to revolve while allowing this base shaft portion to rotate. The rotor drive mechanism (50) is able to distribute and transmit driving force (output from a motor (80)) in parallel to the rotation drive force transmission member (52) and the revolution orbit formation member (56), thereby causing the rotation drive force transmission member (52) and the revolution orbit formation member (56) to rotate while mechanically synchronized, and causing the rotor (20) to revolve while rotating.