There is provided a strain gauge having both reduced size and symmetry. The strain gauge includes at least four grid resistor connected to each other in series, and at least three trim resistors each connected to a series circuit in parallel, the series circuit being constituted by two grid resistors adjacent to each other (R1,R2; R2,R3; R3,R4) of the at least four grid resistors. The at least four grid resistors have resistance values different from one another.