To prevent the peeling-off of a drive circuit chip from an insulation substrate of a display device attributed to a residual stress between terminals formed on the insulation substrate and bumps formed on a mounting surface of a drive circuit chip, as well as to stabilize the connection resistance therebetween, the present invention provides an auxiliary bump for one of the bumps on the mounting surface of the drive circuit chip at an end edge side thereof with respect to the one of the bumps and arranges the auxiliary bump electrically in contact with one of the terminals formed on the insulation substrate of the display device with which the one of the bumps also is in electrical contact. Since the one of the bumps is spaced from the end edge side of the mounting surface of the drive circuit chip by the auxiliary bump, electrical contact thereof with the one of the terminals cannot be affected by the atmosphere, in which the display device is used, and distortion of a signal waveform caused thereat can be suppressed also.