Thrust reverser cascade including acoustic treatment

A cascade type thrust reverser device for a turbomachine of an aircraft, comprising a thrust reverser cascade and a casing, the cascade extending in a first plane defining a first direction and a second direction and including first cavities, the casing comprising an opening extending in a second plane defining the first direction and a third direction and the opening extending in the third direction orthogonal to said first direction and defining a housing wherein the cascade can be inserted in said first direction, and the casing and said cascade being in relative translation with respect to one another in the first direction between a first position of the device in which the cascade is entirely positioned in the housing and a second position of the device in which said cascade is at least partially outside said housing, wherein the casing comprises an acoustic treatment panel including second cavities extending in a third plane parallel to the first plane, each cavity of the first cavities facing each cavity of the second cavities when the device is in the first position to form an acoustic treatment cell comprising the first cavity and the second cavity.