  The use of high energy transients such as Gamma Ray Bursts (GRBs) as probes
of the distant universe relies on the close collaboration between space and
ground facilities. In this context, the Sino-French mission SVOM has been
designed to combine a space and a ground segment and to make the most of their
synergy. On the ground, the 1.3 meter robotic telescope COLIBRI, jointly
developed by France and Mexico, will quickly point the sources detected by the
space hard X-ray imager ECLAIRs, in order to detect and localise their
visible/NIR counterpart and alert large telescopes in minutes. COLIBRI is
equipped with two visible cameras, called DDRAGO-blue and DDRAGO-red, and an
infrared camera, called CAGIRE, designed for the study of high redshift GRBs
candidates. Being a low-noise NIR camera mounted at the focus of an
alt-azimutal robotic telescope imposes specific requirements on CAGIRE. We
describe here the main characteristics of the camera: its optical, mechanical
and electronics architecture, the ALFA detector, and the operation of the
camera on the telescope. The instrument description is completed by three
sections presenting the calibration strategy, an image simulator incorporating
known detector effects, and the automatic reduction software for the ramps
acquired by the detector. This paper aims at providing an overview of the
instrument before its installation on the telescope.
