The resolution of an inverse problem of heat conduction in a three-dimensional plate using an iterative regularization method based on Alifanov’s iterative regularization method is investigated. Considering temperature observation on the upper face centre of a small thin steel plate, the time dependent strength of a plane heat source has to be identified. Two configurations are studied. For the first one, the heat source is fixed on the lower face centre. For the second one, the heat source is mobile and the trajectory is assumed to be known. For both situations, robustness of the approach is stated considering noisy measurements.