A space transformer for connecting a signal source and probing a semiconductor wafer and a manufacturing method thereof are provided. The space transformer includes a circuit board, a redistribution structure bonded to the circuit board, and a conductive through via providing a vertical conductive path therebetween. The circuit board includes a wiring structure which includes alternately stacked dielectric layers and patterned wiring layers, and first contact pads of the patterned wiring layers connect the signal source. The redistribution structure is thinner than the circuit board and includes second contact pads for probing the semiconductor wafer. A pitch of adjacent second contact pads is finer than that of adjacent first contact pads. The conductive through via penetrates through the circuit board, and the conductive through via is laterally covered by the dielectric layers and is laterally and physically in contact with the patterned wiring layers.