An arm muscular strength training and rehabilitation apparatus has a body, an angle meter, a handle, a force sensing device and a main control unit. The body has a housing and a variable resistance device. The variable resistance device is disposed in the housing. The angle meter is disposed on the variable resistance device. The handle is disposed pivotally on the variable resistance device and has a suspension arm and a handlebar bracket. The force sensing device is disposed on handlebar bracket of the handle. The main control unit connects electrically to the variable resistance device, the angle meter and the force sensing device to receive the angle signal and the force sensing signal and controls resistance of the variable resistance device according to the angle signal and the force sensing signal. The apparatus disposing the force sensing device on the handle prevents measuring time lag and increase measuring precision.