Amplified spontaneous emission (ASE) from single rotational levels of Rydberg states, 4p sigma M (2) Sigma(+), 4p pi K (2) Pi, 5s sigma S (2) Sigma(+), 4d sigma O (2) Sigma(+), 4d pi O' (2) Pi, 5p sigma R (2) Sigma(+), and 5p pi Q (2) Pi of NO molecules has been investigated through optical-optical double resonance excitation via the A (2) Sigma(+) state. Several new inter-Rydberg transitions were identified in the midinfrared region. The rotational structure in dispersed ASE spectra was resolved completely, which provided detailed information on cascading radiative relaxation processes among Rydberg states.