An element 1 has: a pair of electrodes 2 and 3; and a deformable middle layer 4 that is disposed between the pair of electrodes 2 and 3, and contains a silicon compound having unpaired electrons as amaterial thereof. The middle layer 4 may contain particles having unpaired electrons. The middle layer 4 may have rubber elasticity. The middle layer 4 may have at least one peak between a g value of2.070 to 2.001 when measured in an ambient temperature of -150 DEG C using an electron spin resonance (ESR) device. The middle layer 4 may have at least one peak between a g value of 2.070 to 2.001 when measured in an ambient temperature of -150 DEG C using an electron spin resonance (ESR) device.