A printer shaped like a slim box includes a carriage which reciprocates in a main scanning direction on its front section. Ink cartridges separately from the carriage are detachably provided in an ink cartridge unit in a row in the main scanning direction above a main scanning area of the carriage. The ink cartridge unit is designed to retreat from an area in the vicinity of the main scanning area of the carriage by sliding in a backward direction of the printer, whereby maintenance work can be easily performed when a trouble (e.g. paper jam) occurs in a recording paper transfer path via an area below a bottom section of the carriage.