The Man-hour refer to the standard time as the sum of the normal time and the allowance time in shipbuilding industry. In domestic shipyards, man-hour is estimated for all process procedures based on empirical data including allowance time measured by a non-engineering method. This method is not applicable to new ships, processes, facilities and is only available in specific shipyards. Estimation of inaccurate man-hour can cause safety accidents and delays in delivery which results in great economic loss. Shipbuilding industry is labor-intensive industry in which worker's skill, effort, consistency and environment factors are great affect to man-hour. However, domestic shipyards do not consider these factors yet. This research intends to estimate the man-hour by formulating the 3D CAD model and the block assembly process to calculate the normal time logically, and estimating the reasonable allowance time by the International Labor Organization table. The man-hour which considers human variety is calculated by The Westinghouse Rating System which considers certain conditions such as worker's skill, effort, consistency and environment factors. The man-hour which considers human variety aims to contribute to planning a more flexible schedule by approaching probabilistically.