The effect of the measuring process on the magnitude of the inter-particle interaction has been investigated by measuring the superparamagnetic relaxation for magnetite particles dispersed in calciumsilicate glasses using thermoremanent magnetization (TRM), AC susceptibility and Mossbauer spectroscopy measurements: The temperature dependence of the remanent magnetization in TRM measurements can be explained by Neel's theory which describes the superparamagnetic relaxation of a noninteracting particle. On the other hand, the relation between log 1 0 τ m (τ: the measurement time) and 1/T B (T B : the average blocking temperature) in AC susceptibility measurements can be interpreted using Dormann's model in which the inter-particle interaction is taken into account. Therefore, it can be concluded that the measuring process for the superparamagnetic relaxation can be more or less sensitive to the inter-particle interaction.