PROBLEM TO BE SOLVED: To measure a bioelectric signal simply when necessary.SOLUTION: A bioelectric signal measurement system comprises a wearable electrode 1100 and a bioelectric signal measurement device 1200. The wearable electrode 1100 is provided with: a flexible electrode 1102 fixed on a surface of clothes 1101 in contact with the skin of a wearer and an SPST switch 1104 which is arranged on the opposite surface to the surface of the clothes in contact with the wearers skin, is turned on when pressure is applied by the wearer and is turned off when the pressure is not applied. The bioelectric signal measurement device 1200 starts measuring a bioelectric signal in accordance with turning on of the SPST switch 1104 when it is connected to the wearable electrode 1100.