Provided are a thermoelectric conversion element and a thermoelectric conversion module using the thermoelectric conversion element. The thermoelectric conversion element has a first substrate having a high thermal conduction portion which has a thermal conductivity higher than a thermal conductivity of other regions, a thermoelectric conversion layer formed on the first substrate, a pressure sensitive adhesive layer formed on the thermoelectric conversion layer, a second substrate formed on the pressure sensitive adhesive layer, having a concave portion, which at least partially overlaps the high thermal conduction portion of the first substrate in a plane direction and is on the pressure sensitive adhesive layer side, and made of a metal material, and an electrode pair connected to the thermoelectric conversion layer. According to the present invention, a thermoelectric conversion element and a thermoelectric conversion module are obtained which improve the heat utilization efficiency and generate electric power with excellent efficiency.