A printer comprising a roll storage part, a feeder, a printing head, a first guide member, a second guide member, and a driving gear. The first and second guide members guide a print-receiving medium in a width direction and provided in an advanceable and retreatable manner. The driving gear makes the first and second guide members advance and retreat. The roll storage part comprises a first through-hole for guiding the first guide member in the width direction, and a second through-hole for guiding the second guide member in the width direction. The first guide member comprises a first driven part configured to mesh with the driving gear, and a first sandwiching part holding the first guide member. The second guide member comprises a second driven part configured to mesh with the driving gear, and a second sandwiching part holding the second guide member.