A separator for a fuel cell, which is configured to be stacked on a gas diffusion layer provided on a membrane electrode assembly, MEA, the separator comprising: a plate body configured to be stacked on the gas diffusion layer and comprising a flow path part configured to define a reaction region configured to react with the membrane electrode assembly, and manifold parts spaced apart from the flow path part; through-holes disposed in the plate body and configured to guide target fluids that have passed through the manifold parts to the flow path part; hole caps disposed on one surface of the plate body that faces the gas diffusion layer and configured to at least partially cover the through-holes, the hole caps being configured to define movement paths through which the target fluids move, wherein each hole cap comprises: a side cap portion disposed on an edge of the respective through-hole; and a top cap portion spaced apart from the plate body, configured to cover the respective through-hole, and supported by the side cap portion, wherein the movement path is defined in a space between the top cap portion and the plate body, and a reinforcing part configured to support the hole cap on the plate body, wherein each reinforcing part comprises: a center reinforcing member connected to an inner surface of the top cap portion; a first side reinforcing member having a first end connected to a first side surface of the center reinforcing member and a second end connected to the plate body; and a second side reinforcing member having a first end connected to a second side surface of the center reinforcing member and a second end connected to the plate body. a plate body configured to be stacked on the gas diffusion layer and comprising a flow path part configured to define a reaction region configured to react with the membrane electrode assembly, and manifold parts spaced apart from the flow path part; through-holes disposed in the plate body and configured to guide target fluids that have passed through the manifold parts to the flow path part; hole caps disposed on one surface of the plate body that faces the gas diffusion layer and configured to at least partially cover the through-holes, the hole caps being configured to define movement paths through which the target fluids move, wherein each hole cap comprises: a side cap portion disposed on an edge of the respective through-hole; and a top cap portion spaced apart from the plate body, configured to cover the respective through-hole, and supported by the side cap portion, wherein the movement path is defined in a space between the top cap portion and the plate body, and a reinforcing part configured to support the hole cap on the plate body, wherein each reinforcing part comprises: a center reinforcing member connected to an inner surface of the top cap portion; a first side reinforcing member having a first end connected to a first side surface of the center reinforcing member and a second end connected to the plate body; and a second side reinforcing member having a first end connected to a second side surface of the center reinforcing member and a second end connected to the plate body. a side cap portion disposed on an edge of the respective through-hole; and a top cap portion spaced apart from the plate body, configured to cover the respective through-hole, and supported by the side cap portion, wherein the movement path is defined in a space between the top cap portion and the plate body, and a reinforcing part configured to support the hole cap on the plate body, wherein each reinforcing part comprises: a center reinforcing member connected to an inner surface of the top cap portion; a first side reinforcing member having a first end connected to a first side surface of the center reinforcing member and a second end connected to the plate body; and a second side reinforcing member having a first end connected to a second side surface of the center reinforcing member and a second end connected to the plate body. a center reinforcing member connected to an inner surface of the top cap portion; a first side reinforcing member having a first end connected to a first side surface of the center reinforcing member and a second end connected to the plate body; and a second side reinforcing member having a first end connected to a second side surface of the center reinforcing member and a second end connected to the plate body.