PURPOSE: To obtain a load detecting device of a press, which has improved its detecting accuray and environmental adaptability of equipment, by converting expansion and contraction of a frame of the press to the extent of bending of a spring, and detecting voltage responding to this extent of bending through a distortion gauge type load sensor.

CONSTITUTION: An output of a load sensor 3 for outputting voltage responding to load of a press is an analog signal, and it is converted to a digital signal by an A/D converter 8. Subsequently, the converted digital load signal is supplied to a compensation device 9, and said load signal is compensated in accordance with environment for the operation of press, that is to say, an ambient temperature of the press, input voltage, etc. Also, whether load of the press is proper or not is decided by inputting the compensated digital signal to an operating device 10, and an output signal is applied to each indicator. In this regard, in the figure, 1 and 2 denote a guide and a pin, respectively, and the sensor 5 is inserted and fixed under the pin 2. Also, on the upper surface of the sensor 3, a spring seat 5 is superposed, and between this seat 5 and the lower end part of the pin 2, a spring 6 is stretched and provided.