1. A posture estimating apparatus comprising: at least one processor and memory coupled to each other and configured to: input a range image including a multi joint object; derive at least one joint position candidate for each of a first joint position and a second joint position of the multi-joint object, from the input range image; store information including joint position permissible range information for a first joint and a second joint in a multi-joint object model corresponding to the multi-joint object; calculate joint position range information for each combination of at least one joint position candidate set to the first joint position of the multi-joint object and at least one joint position candidate set to the second joint position of the multi-joint object; evaluate consistency for each combination by determining whether the calculated joint position range information for each combination is within the joint position permissible range information of the first and second joint positions of the multi-object model; calculate an evaluation value based on likelihoods of the joint position candidates and the evaluated consistencies for all combinations; and estimate a posture of the multi joint object based on the calculated evaluation value.