Disclosed are: a thermally conductive member which is capable of reducing the risk of heat conduction to an adjacent unit cell in order to make the cooling characteristics of unit cells uniform in a battery device wherein the unit cells are aligned; and a battery device using the thermally conductive member. Specifically disclosed is a thermally conductive member which is arranged between two unit cells when a battery is formed by combining unit cells. The thermally conductive member is characterized by having a configuration wherein thermally conductive layers having a thermal conductivity of 0.5 W/mK or more are arranged on both sides of a base layer that has a thermal conductivity of less than 0.5 W/mK. It is particularly preferable that the resin member constituting the base layer has a bending modulus of 1 GPa or more.