To provide a seat load measuring system capable of performing zero adjustment by changing offset voltage every time displacements in the zero point of a load sensor occur.

The seat load measuring system comprises both a load sensor assembly 10 and a load detecting electronic control device 21. The load sensor assembly 10 has both a load sensor 11 for producing load output proportional to load and a two-way communication interface A18. The load detecting electronic control device 21 has two two-way communication interfaces B22 and C23, performs arithmetic operation on the load output inputted from the load sensor indenter via the two-way communication interfaces A18 and B22, and outputs a load signal. By connecting a zerot adjustment command input means 90 of the load sensor to the two-way communication interface C23 and inputting a zero adjustment command, the zero adjustment command is transmitted to the load sensor assembly 10 via the two-way communication interfaces B22 and A18 to change the offset voltage of the load sensor 11 to perform zero adjustment.