A head cap, including: a cap including (a) a bottom plate portion and (b) a projecting portion which functions as a side wall, which extends from the bottom plate portion so as to define a recessed portion with the bottom plate portion, and whose distal end contacts with a surrounding of a liquid-droplets ejecting area formed in a liquid-droplets ejecting surface of a liquid-droplets ejecting head so as to enclose the liquid-droplets ejecting area; a holder configured to support the cap; a groove formed in at least one of a first surface of the bottom plate portion which is opposed to the holder and a second surface of the holder which is opposed to the bottom plate portion so as to partly constitute an air communicating channel that communicates the recessed portion and an outside with each other; and a channel wall provided between the first surface and the second surface so as to enclose the groove as seen in a direction perpendicular to one of the first surface and the second surface by contacting with at least one of the first surface and the second surface.