An ink supply device including an ink cartridge for storing an ink; a mounting portion which includes an opening from which the ink cartridge is removable in a direction; an elastic member which urges the ink cartridge accommodated in the mounting portion to the direction; and a lock member. The lock member includes a lock arm including an operating lever provided at a first end thereof, and a lock portion provided at a second end thereof; a supporting mechanism which movably supports the lock arm between a first posture in which the lock portion is disengaged from the engaged portion and a second posture in which the lock portion is engaged with the engaged portion to regulate a movement of the ink cartridge to the direction; and a stopper which is provided in the lock arm and contacts the ink cartridge when the lock arm takes the first posture.