PURPOSE: To mix plural kinds of bodies to be measured at a specific ratio by carrying a body to be measured to the load call balance and stopping the conveyance of the body to be measured when a measured values attains to a set acceptance area, and performing said operation for every body to be measured successively.

CONSTITUTION: The load cell balance 3 consisting of a balance part 1 and a display part 2 is provided, and a mixing container 4 is placed on the balance part 1. A relay 16 which controls an on-off valve is provided each of outflow pipe 6 of a conveying machine 5. For example, when a 30kg blue, a 15kg yellow, and a 5kg white pigment are mixed, target weights 30kg, 15kg, and 5kg are set on a ten-key keyboard 14, and the target weights and acceptance areas are stored in a RAM10. The blue pigment is supplied from an outflow pipe 6 to a container firstly and the measurement result of the load cell 11 is transmitted to a CPU7 through a ADC13; when the value attains to the acceptance area of 30kg stored in the RAM10, the supply from the outflow pipe 6 is stopped. Then, yellow and white pigments are supplied similarly and the pigments are mixed at the specific ratio.