An X-ray generator comprising a target for receiving electrons and generating X-rays, a separator for dividing an internal space of the target into a coolant inflow path and a coolant outflow path, a motor for rotating the target, and a coolant inflow path and a coolant outflow path for supplying a coolant to the coolant inflow path and recovering the coolant through the coolant outflow path, wherein the separator rotates in the same rotation direction as the target when the target rotates. In the X-ray generator in which a coolant inflow path and a coolant outflow path are provided by a separator inside a rotating target, reduced torque load and reduced vibration can be realized.