PURPOSE: To certainly detect the residual amount of an ink, by providing a transparent part only to the side surface of an ink cassette opposed to an ink tank.

CONSTITUTION: Transparent or translucent parts 8, 9 are provided to the side surfaces of an ink cassette 1 opposed to ink tanks 5, 6 while other parts are finished as similar to the exterior of the apparatus mounted with the ink cassette 1. Therefore, the residual amounts of inks in the ink tanks 5, 6 are certainly detected without damaging the appearance of the apparatus while a waste ink sump is provided to the part of the ink cassette 1 to reduce the occupying space thereof in the apparatus and the miniaturization of the apparatus is attained.