A printing unit, comprising: a platen unit including a platen roller configured to feed a recording sheet; and a head unit including a thermal head configured to perform printing on the recording sheet, the head unit being separably combined with the platen unit, the head unit including: a head frame; a cutter mechanism, the cutter mechanism being configured to cut the recording sheet; and a support member provided between the cutter mechanism and the head frame, characterized in that: the support member is movable relative to the head frame and the cutter mechanism between a coupled position at which the cutter mechanism is coupled to the head frame and the support member, and a decoupled position at which the cutter mechanism is decoupled from the support member and is detachable from the head frame, whereby the cutter mechanism is mounted to the head frame in a removable manner by the intermediation of the support member; and a first urging member interposed between the thermal head and the support member, the first urging member being configured to urge the thermal head toward the platen roller, and to urge the support member toward the coupled position. a platen unit including a platen roller configured to feed a recording sheet; and a head unit including a thermal head configured to perform printing on the recording sheet, the head unit being separably combined with the platen unit, the head unit including: a head frame; a cutter mechanism, the cutter mechanism being configured to cut the recording sheet; and a support member provided between the cutter mechanism and the head frame, characterized in that: the support member is movable relative to the head frame and the cutter mechanism between a coupled position at which the cutter mechanism is coupled to the head frame and the support member, and a decoupled position at which the cutter mechanism is decoupled from the support member and is detachable from the head frame, whereby the cutter mechanism is mounted to the head frame in a removable manner by the intermediation of the support member; and a first urging member interposed between the thermal head and the support member, the first urging member being configured to urge the thermal head toward the platen roller, and to urge the support member toward the coupled position. a head frame; a cutter mechanism, the cutter mechanism being configured to cut the recording sheet; and a support member provided between the cutter mechanism and the head frame, characterized in that: the support member is movable relative to the head frame and the cutter mechanism between a coupled position at which the cutter mechanism is coupled to the head frame and the support member, and a decoupled position at which the cutter mechanism is decoupled from the support member and is detachable from the head frame, whereby the cutter mechanism is mounted to the head frame in a removable manner by the intermediation of the support member; and a first urging member interposed between the thermal head and the support member, the first urging member being configured to urge the thermal head toward the platen roller, and to urge the support member toward the coupled position. the support member is movable relative to the head frame and the cutter mechanism between a coupled position at which the cutter mechanism is coupled to the head frame and the support member, and a decoupled position at which the cutter mechanism is decoupled from the support member and is detachable from the head frame, whereby the cutter mechanism is mounted to the head frame in a removable manner by the intermediation of the support member; and a first urging member interposed between the thermal head and the support member, the first urging member being configured to urge the thermal head toward the platen roller, and to urge the support member toward the coupled position. a first urging member interposed between the thermal head and the support member, the first urging member being configured to urge the thermal head toward the platen roller, and to urge the support member toward the coupled position.