A printing apparatus includes an ejecting head that ejects ink droplets onto a surface of a printing medium (paper roll), a carriage on which the ejecting head is mounted, a platen that faces the ejecting head and supports the printing medium, a detector plate provided in the carriage and is displaced in accordance with an external force applied in response to contact with the printing medium, and an encoder that measures a displacement amount of the detector plate and outputs an output value corresponding to the displacement amount.