PURPOSE: To obtain an estimating device for this plate working by which the optimum estimate is obtained without requiring skillfulness.

CONSTITUTION: The estimating device is provided with a storing means 1, calculating means 2, inputting means 3 and displaying and printing-means 4. Plural working conditions which can be selected and are preliminarily inputted and their standard price, material and its unit price per unit area, dimensions of a regular sized material and the price of material, surface treatment conditions and a controlling procedure practised by the calculating means 2 are stored by the storing means 1. According to the controlling procedure, based on a unit price per hour of working machine and number and dimensions of works inputted by the inputting means 3, working conditions, material and surface treatment conditions selected from those stored by the storing means 1, the price for each working is calculated and, based on the dimension of work, the optimum material cutting from regular sized material is calculated and the lowest material cost is selected among them and the total price and material price are outputted to the displaying or printing means 4.