A multilayer rigid-flex circuit board is provided. The multilayer rigid-flex circuit board includes at least one rigid circuit section, at least one flex circuit section disposed to face the rigid circuit section, and circuit layers disposed to be extended and formed in equal layers within the rigid circuit section and the flex circuit section. The flex circuit section may include a coverlay disposed to face a dielectric layer of the rigid circuit section and formed above or below the circuit layer disposed within the flex circuit section. The coverlay may include a coverlay film, and a first cover resin layer and a second cover resin layer respectively laminated on opposite surfaces of the coverlay films. Since high-speed wiring and interlayer separation, which may occur in a multilayer structure, are eliminated, it is possible to reduce noise and to achieve signal integrity and stabilization of radio frequency interference (RFI).