A recording medium cutter capable of moving between two positions, a cutting position and a non-cutting position, in a short time, and also capable of cutting a recording medium at accurate positions. A main body (40) rotatably holding a rotary blade (32) and a driven blade (34) is located between side plates (36 and 38) of the cutter (30). A main shaft (39) serving as the center shaft of the rotary blade (32) is rotatably secured to the side plates (36 and 38). The main shaft (39) also serves as the rotating shaft of the main body (40). A driving motor is secured to the mounting plate (42) of the side plate (36). When the main shaft (39) is rotated by the driving motor (44), the rotary blade (32) rotates. Because the driven blade (34) is pressed against the side face of the rotary blade (32), as the rotary blade (32) rotates, the driven blade (34) revolves around the main shaft (39). As a result, the main body (40) also rotates around the main shaft (39). When the main body (40) is moved from the non-cutting position to the cutting position, the rotation of the main body (40) is stopped the moment that a stopper (41) of the main body (40) comes into contact with a stopping plate (50), whereas the rotary blade (32) continues to rotate. When the main body (40) is moved from the cutting position to the non-cutting position, the rotation of the main body (40) is stopped the moment that a lever (58), engaged with the main body during rotation, comes into contact with a hole's extreme end (38) of the side plate (38). At this time, a sensor bar (60) of the lever (58) turns a sensor (62) off, causing the driving motor (44) to be turned off.