PROBLEM TO BE SOLVED: To provide a low noise amplifier (LNA) having high linear characteristics, which improves an input reference secondary intercept point (IIP2) and a noise factor (NF).SOLUTION: A signal input part 110 applies signals with the same phase to a first current leading-in end (source) of a first amplifier gm1, and a second current leading-in end (source) of a second amplifier gm2, respectively, by using capacitors C1 and C2 for DC blocking of single input of an input signal. A fact that the signal input part of a low noise amplifier 100 is divided into the first amplifier and the second amplifier to receive input is for improving secondary mutual modulation distortion and a noise factor. The signal input part comprises a first bias circuit 112 and a second bias circuit 114. The first bias circuit, the second bias circuit and one input signal of the signal input part are connected with one another.