α‐Galactosylceramide (α‐GalCer) activates invariant (i)NKT cells, which in turn stimulate immunocompetent cells. Although activation of iNKT cells appears critical for regulation of immune responses, it remains elusive whether protection against intracellular bacteria can be induced by α‐GalCer. Here, we show that α‐GalCer treatment ameliorates murine listeriosis, and inhibits inflammation following Listeria monocytogenes infection. Liver infiltration of Gr‐1+ cells and γ/δ T cells was accelerated by α‐GalCer treatment. Gr‐1+ cell and γ/δ T‐cell depletion exacerbated listeriosis in α‐GalCer‐treated mice, and this effect was more pronounced after depletion of Gr‐1+ cells than that of γ/δ T cells. Although GM‐CSF and IL‐17 were secreted by NKT cells after α‐GalCer treatment, liver infiltration of Gr‐1+ cells was not prevented by neutralizing mAb. In parallel to the numerical increase of CD11b+Gr‐1+ cells in the liver following α‐GalCer treatment, CD11b−Gr‐1+ cells were numerically reduced in the bone marrow. In addition, respiratory burst in Gr‐1+ cells was enhanced by α‐GalCer treatment. Our results indicate that α‐GalCer‐induced antibacterial immunity is caused, in part, by accelerated infiltration of Gr‐1+ cells and to a lesser degree of γ/δ T cells into the liver. We also suggest that the infiltration of Gr‐1+ cells is caused by an accelerated supply from the bone marrow.