A printing unit , comprising: a head unit including a thermal head configured to perform printing on a recording sheet (P); a platen unit , which includes a platen roller configured to convey the recording sheet (P), and is separably combined with the head unit ; a fixed blade provided to any one of the head unit and the platen unit ; a movable blade , which is provided to another one of the head unit and the platen unit , and is relatively movable with respect to the fixed blade ; a drive mechanism , which includes a drive rack coupled to the movable blade , and is configured to move the movable blade between a standby position (P2) being separated from the fixed blade and a cutting position (P1) at which the movable blade rides on the fixed blade ; an operation lever being movable between a lock position (P3) at which the platen unit is locked to the head unit and a releasing position (P5) at which the platen unit is unlocked from the head unit ; and a return mechanism configured to move the movable blade from the cutting position (P1) toward the standby position (P2) side under a state in which the movable blade is stopped at the cutting position (P1), characterized in that the return mechanism includes a lever returning mechanism configured to, under the state in which movable blade is stopped at the cutting position (P1), transmit motive power generated along with an operation of the operation lever from the lock position (P3) toward the releasing position (P5) to the drive mechanism to move the movable blade toward the standby position (P2) and to return the operated operation lever from the releasing position (P5) side to the lock position (P3). a head unit including a thermal head configured to perform printing on a recording sheet (P); a platen unit , which includes a platen roller configured to convey the recording sheet (P), and is separably combined with the head unit ; a fixed blade provided to any one of the head unit and the platen unit ; a movable blade , which is provided to another one of the head unit and the platen unit , and is relatively movable with respect to the fixed blade ; a drive mechanism , which includes a drive rack coupled to the movable blade , and is configured to move the movable blade between a standby position (P2) being separated from the fixed blade and a cutting position (P1) at which the movable blade rides on the fixed blade ; an operation lever being movable between a lock position (P3) at which the platen unit is locked to the head unit and a releasing position (P5) at which the platen unit is unlocked from the head unit ; and a return mechanism configured to move the movable blade from the cutting position (P1) toward the standby position (P2) side under a state in which the movable blade is stopped at the cutting position (P1), characterized in that the return mechanism includes a lever returning mechanism configured to, under the state in which movable blade is stopped at the cutting position (P1), transmit motive power generated along with an operation of the operation lever from the lock position (P3) toward the releasing position (P5) to the drive mechanism to move the movable blade toward the standby position (P2) and to return the operated operation lever from the releasing position (P5) side to the lock position (P3). <EOS>