This paper proposes a 4-DOF (degrees-of-freedom) n-RER parallel manipulator (PM) with congruent base and moving platform (CBP). The 4-DOF n-RER PM is composed of a base and a moving platform connected by n RER legs, each of which is a serial kinematic chain composed of a revolute (R) joint, a planar (E) joint and an R joint in sequence. At first, a set of constraint equations of the n-RER PM with CBP is first derived. It is then found that like the 3-RER PM with congruent triangular base and platform in the literature, the n-RER PM with CBP has three 4-DOF operation modes regardless of the number of legs (n > 2) and link parameters. The characteristics of the n-RER PM with CBP in different operation modes are also presented.