At present, in mechanical engineering there is a tendency of small-scale production due to the peculiarities and requirements of the market. At the same time, machine-building enterprises have to account the costs of produced products accurately (both for the state defense order and for the open market). The problem of the product labor intensity calculation becomes urgent, as it is used as a basis for of the product full cost calculation. Taking into account the technology changes, equipment, peculiarities of production program formation (small or medium series), using the existing approaches, work norms manuals becomes impossible. The investigation presents an improved algorithm for the work norm calculating using for the main workers in the high-tech production. A feature of the proposed approach is taking into account the share of passive observation during the technological operations in conditions of small-scale production in the conditions of the high-tech production. The article presents the results of the proposed method testing. The approbation was realized at the industrial enterprise in the conditions of the small-scale production. Proposed algorithm for work norms calculation can be used in automation of labor rationing at the industrial enterprise.