An apparatus for manufacturing panels made of expanded plastic material comprising at least one perimetric confinement frame clamped between a pair of pressing surfaces of a press in order to delimit laterally at least one expansion cavity for an expanding mixture. At least one portion of the perimetric frame defines internally, along its extension, at least one air passage channel that is connected to at least one air intake port, which is defined in the surface of the perimetric frame that is directed toward the inside of the expansion cavity, and to at least one connection port, which is defined in the surface of the perimetric frame that is directed toward the outside of the expansion cavity and adapted to be connected to at least one air suction device.