A surface electromyogram (EMG), which measures a voltage waveform produced by skeletal muscles on skin, is an important tool for applications detecting the human will of motion, such as for prosthetic hands and prosthetic legs. In the application to a prosthetic hand, a multipoint EMG measurement is required to precisely control the hand [1, 2]. Conventional multipoint measurements with a passive electrode array [1-3], however, have two problems: 1) Measurement over a long time period is annoying, because the EMG electrodes placed on the skin are rigid, and 2) the signal integrity of EMG is degraded, because the number of wires between the electrodes and the front-end circuits increases with increasing number of measurement points. To address these challenges, a surface EMG measurement sheet (SEMS) on which an EMG electrode array and a front-end amplifier array with 2V organic transistors are integrated on a 1μm-thick ultra-flexible film is developed to control prosthetic hands. The developed SEMS enables a comfortable long-time measurement without signal integrity degradation.