A printer comprising: a main-body case; a housing portion configured to house substantially sheet-shaped media to be printed as a print object therein, said housing portion being openable on one side of said main-body case; a pickup roller configured to pick up and feed said medium to be printed toward a first direction along a surface direction of said medium, said pickup roller being disposed in said housing portion; a platen roller configured to feed said medium to be printed, said medium being fed toward said first direction by said pickup roller, said platen roller being provided on the first direction side of said pickup roller; a print head configured to perform desired printing on said medium to be printed being fed; a paper guide configured to reverse, in cooperation with said print head, said medium to be printed toward a second direction in opposite to said first direction while feeding said medium to be printed along an outer peripheral surface of said platen roller, said paper guide including at least one arc-shaped surface portion provided along said outer peripheral surface of said platen roller in an opposed manner thereto; and a coupling member that couples between said paper guide and a rotation shaft of said platen roller so as to keep a predetermined gap (Δ) between said arc-shaped surface portion of said paper guide and said outer peripheral surface of said platen roller, said coupling member includes a shaft holding portion that holds said rotation shaft of said platen roller while allowing rotation of said rotation shaft, characterized in that said coupling member includes a beam portion that extends toward said first direction from said shaft holding portion and couples between said shaft holding portion and said paper guide. a main-body case; a housing portion configured to house substantially sheet-shaped media to be printed as a print object therein, said housing portion being openable on one side of said main-body case; a pickup roller configured to pick up and feed said medium to be printed toward a first direction along a surface direction of said medium, said pickup roller being disposed in said housing portion; a platen roller configured to feed said medium to be printed, said medium being fed toward said first direction by said pickup roller, said platen roller being provided on the first direction side of said pickup roller; a print head configured to perform desired printing on said medium to be printed being fed; a paper guide configured to reverse, in cooperation with said print head, said medium to be printed toward a second direction in opposite to said first direction while feeding said medium to be printed along an outer peripheral surface of said platen roller, said paper guide including at least one arc-shaped surface portion provided along said outer peripheral surface of said platen roller in an opposed manner thereto; and a coupling member that couples between said paper guide and a rotation shaft of said platen roller so as to keep a predetermined gap (Δ) between said arc-shaped surface portion of said paper guide and said outer peripheral surface of said platen roller, said coupling member includes a shaft holding portion that holds said rotation shaft of said platen roller while allowing rotation of said rotation shaft,