Abstract: The inventive concept provides an apparatus for treating a substrate. A substrate treatment apparatus according to an embodiment includes a housing having a treatment space in which the substrate is treated, a support unit that supports the substrate in the treatment space, and a gas supply unit that supplies a gas to the treatment space, wherein a heat transfer flow path that supplies a heat transfer medium to the substrate supported by the support unit, a pin hole defining an elevation path of a lift pin that elevates the substrate supported by the support unit, and a connection portion allowing the heat transfer flow path and the pin hole to be in communication with each other are formed inside the support unit, and the connection portion includes a porous structure.