The inflationary scenario is formulated so far by the introduction of (elementary) scalar fields (called inflaton) with a nearly flat potential. However, we can imagine the possibility that the inflaton need not be an elementary degree of freedom. In this talk, we revisit the cosmological scenario in which the inflaton is a composite field emerging in the scalar channel of the effective Nambu–Jona-Lasinio (NJL) model. We demonstrate that it is viable to achieve successful inflation via a non-minimal coupling to gravity. We also compute the inflationary parameters and confront them with Planck data.