We present a study of the kinematic properties of the ionized gas in the dominant giant H II region of the well known H II galaxy: II Zw 40. High spatial and spectral resolution spectroscopy has been obtained using the Integral Field Unit mode on the Gemini Multi-Object Spectrograph instrument at the Gemini-North7Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (USA), the Science and Technology Facilities Council (UK), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), CNPq (Brazil), and CONICET (Argentina). telescope. The observations allow us to obtain the Halpha intensity map, the radial velocity and velocity dispersion maps as well as estimate some physical conditions in the inner region of the starburst, such as oxygen abundance (O/H) and electron density. We have used a set of kinematics diagnostic diagrams, such as the intensity versus velocity dispersion (I-sigma), intensity versus radial velocity (I-V), and V-sigma, for global and individual analysis in the subregions of the nebula. We aim to separate the main line broadening mechanisms responsible for producing a smooth supersonic integrated line profile for the giant H II region. Bubbles and shells driven by stellar winds and possibly supernovae, covering a large fraction on the face of the nebula, are identified on scales larger than 50 pc. We found that unperturbed or "free from shells" regions showing the lowest sigma values (~20 km s-1) should be good indicators for the sigmagrav component in II Zw 40. The brightest central region (R ~ 50 pc) is responsible for sigma derived from a single fit to the integrated line profile. The dominant action of gravity, and possibly unresolved winds of young (