This work investigates the bandgap property of a membrane-type metamaterial (MemM) consisting of a periodically arranged membrane-type resonators. Each resonator is constructed of a circular-shaped mass that is located inside an annular-shaped mass and both decorated masses are concentrically attached to the middle of a pre-stressed membrane. The proposed configuration of decorated masses is designed to allow the metamaterial to generate multiple local resonant bandgaps. The vibration mode shapes of this configuration are investigated through numerical simulation so to reveal the bandgap forming mechanism. A stacked resonator structure of membrane-type metamaterial is normally required when multiple bandgaps are in demand. Therefore, when a metamaterial with multiple bandgaps are required, the proposed membrane-type metamaterial has the space-saving advantage in contrast to using a stacked structure of resonators. Through numerical simulation studies of membrane-type resonators with dual decorated masses, the feasibility of adjusting the geometry of decorated masses to achieve multiple bandgaps is demonstrated.