A coated cBN sintered body tool comprising a substrate of a cBN sintered body and a coating layer coated on the surface thereof, wherein the cBN sintered body comprises 73 to 84% by volume of cBN; and 16 to 27% by volume of a binder phase which comprises at least one selected from the group consisting of a metal of Ti, W, Co and Al, a carbide, carbonitride, a nitride, a boronitride, a boride and an oxide of these metals and a mutual solid solution thereof, and inevitable impurities; an average grain size of the cBN is 1.5 to 4.0 μm, an average value of the thickness of the binder phase is 0.05 to 0.5 μm, a standard deviation of a thickness of the binder phase is 0.5 μm or less, the coating layer comprises an upper layer, an intermediate layer, a lower layer and an undermost layer, the upper layer comprises a compound represented by a compositional formula of Ti(C x N (1-x)), wherein x represents an atomic ratio of C based on the total amount of C and N, and satisfies 0≦x≦0.7, and has an average layer thickness of 0.3 to 2.0 μm, the intermediate layer comprises at least one metal selected from the components of Ti, Al, Cr and Si, and has an average layer thickness of 10 to 100 nm, the lower layer comprises an alternately laminated layer comprising a first thin layer which comprises a compound represented by a compositional formula of (Ti (1-y) Si y)N wherein y represents an atomic ratio of Si based on the total amount of Ti and Si, and satisfies 0.01≦y≦0.3, and has an average layer thickness of 30 to 200 μm, and a second thin layer which comprises a compound represented by a compositional formula of (Al (1-z) Cr z)N wherein z represents an atomic ratio of Cr based on the total amount of Al and Cr, and satisfies 0.2≦z≦0.5, and has an average layer thickness of 30 to 200 nm, the first and second thin layers being alternately laminated with an average layer thickness of 0.12 to 1.6 μm with respect to the whole alternately laminated layer, and the undermost layer comprises a compound represented by a compositional formula of (Al (1-a) Cr a)N wherein a represents an atomic ratio of Cr based on the total amount of Al and Cr, and satisfies 0.2≦a≦0.5, and has an average layer thickness of 20 to 200 nm. the upper layer comprises a compound represented by a compositional formula of Ti(C x N (1-x)), wherein x represents an atomic ratio of C based on the total amount of C and N, and satisfies 0≦x≦0.7, and has an average layer thickness of 0.3 to 2.0 μm, the intermediate layer comprises at least one metal selected from the components of Ti, Al, Cr and Si, and has an average layer thickness of 10 to 100 nm, the lower layer comprises an alternately laminated layer comprising a first thin layer which comprises a compound represented by a compositional formula of (Ti (1-y) Si y)N wherein y represents an atomic ratio of Si based on the total amount of Ti and Si, and satisfies 0.01≦y≦0.3, and has an average layer thickness of 30 to 200 μm, and a second thin layer which comprises a compound represented by a compositional formula of (Al (1-z) Cr z)N wherein z represents an atomic ratio of Cr based on the total amount of Al and Cr, and satisfies 0.2≦z≦0.5, and has an average layer thickness of 30 to 200 nm, the first and second thin layers being alternately laminated with an average layer thickness of 0.12 to 1.6 μm with respect to the whole alternately laminated layer, and the undermost layer comprises a compound represented by a compositional formula of (Al (1-a) Cr a)N wherein a represents an atomic ratio of Cr based on the total amount of Al and Cr, and satisfies 0.2≦a≦0.5, and has an average layer thickness of 20 to 200 nm.