A cryostat has been developed for qualification tests on the various cryomechanisms of the ISOPHOT photometer in the Infrared Space Observatory (ISO), permitting vibration of the assemblies involved under extremely clean conditions and at the temperature of liquid nitrogen. In this cryostat, the three different change wheels of ISOPHOT, whose weight including the respective supporting structures is almost-equal-to 2 kg, can be subjected to excessive vibration loads at 80 K. This substantially exceeds the specified ISOPHOT test loads in certain parts, due to the elasticity of the ISOPHOT support structure. Following an outline of the design features, a report is given of the measured properties of the vibration test cryostat.