To provide a printer capable of easily offering enhanced speed.

A carriage 20 is accelerated in one direction and brought into a constant-speed state, decelerated after being kept in the constant-speed state for some time, accelerated in the reverse direction again, and decelerated after being kept in the constant-speed state, so as to be repeatedly reciprocated in a reciprocating section. In the stop of the carriage 20 in a retreating position and the like, the carriage 20 is judged to be stopped, when an encoder signal is not changed for 100 ms. In the case where the carriage 20 is reversed during printing, the carriage 20 is judged to be stopped, when the encoder signal is not changed for 5 ms.