The vector processor of the present invention is designed to have a first function for classifying, generating and storing in advance a separate index set by judging the attribute of specified data and a second function for continuously performing operand access only for the index value belonging to the specified index set out of the index sets generated by the first function, thus avoiding the deterioration of the efficiency of pipeline processing even when the calculation of array data has different operation content according to the attributes of the specified data. Accordingly it can perform continuous calculation of a plurality of different conditioned expressions at high speed by arranging it to operate the first and the second functions concurrently with the value resulting from the operation by the second function being used by the first function as a data for discriminating the attribute of the data.