We present a new type of quantum critical material YbCo2Ge4, having the largest quantumcritical pseudospin size ever. The YbCo2Ge4-type structure is new, forms in the orthorhombic Cmcm system, and is related to the well-known ThCr2Si2 structure. Heavy rare earth (Tm,Yb,Lu, or Y) members are also possible to be grown. YbCo2Ge4 possesses the Ising-type ground-state doublet, namely the simplest ones of uniaxially up or down, |± ∼ 7/2 . It is clearly manifested through comprehensive resistivity, magnetization, specific heat, and NQR/NMR experiments. Large pseudospin state usually tends to order in simple magnetisms, or hard to be screened by Kondo effect. Therefore, the discovery of the quantum criticality of the fluctuating large spins opens a new door to new-material search and theoretical studies.