The temperature dependence of photoluminescence (PL) properties of AlGaAs/GaAs quantum wire (QWR) grown on V‐grooved substrates by flow rate modulation epitaxy is investigated. PL from a 7.1 nm thick QWR is easily observed even at room temperature. The full width at half‐maximum (FWHM) of the QWR emission peak increases linearly with increasing temperature at low temperatures and becomes almost independent of temperature at high temperatures, while that of a quantum well layer (QWL) sample increases with increasing temperature up to room temperature. The FWHM of QWR is found to be considerably narrower than that of the QWL sample at high temperatures, which is expected theoretically from the sharp one‐dimensional density of states of QWR but has not been clearly observed experimentally. ©1995 American Institute of Physics.