The present invention provides a β-type titanium alloy keeping the content of the relatively expensive β-stabilizing elements such as V or Mo down to a total of 10 mass % or less and reducing the effects of composition segregation of Fe and Cr and thereby able to keep the Young's modulus and density relatively low. The β-type titanium alloy of the present invention comprises, by mass %, when Al: 2 to 5%, 1) Fe: 2 to 4%, Cr: 6.2 to 11%, and V: 4 to 10%, 2) Fe: 2 to 4%, Cr: 5 to 11%, and Mo: 4 to 10%, or 3) Fe: 2 to 4%, Cr: 5.5 to 11%, and Mo+V (total of Mo and V): 4 to 10% in range, and a balance of substantially Ti. These include Zr added in amounts of 1 to 4 mass %. Furthermore, by making the oxygen equivalent Q 0.15 to 0.30 or leaving the alloy in the work hardened state or by applying both, the tensile strength before aging heat treatment can be further increased. Due to this, it is possible to obtain the required strength even if the amount of precipitation of the α phase with the high Young's modulus is small.