The purpose of the present invention is to make it possible to ensure a strength that allows thermoelectric evaluation to be performed even when sintering is carried out at a temperature lower than the minimum sintering temperature of a power generation layer, in a thermoelectric conversion element. For this purpose, this thermoelectric conversion element is characterized by being provided with a power generation layer and support layers including a sintered body, wherein the power generation layer is provided with a metal-magnetic insulator composite structure in which metal is formed in a net shape around a granulated magnetic body, the support layers are formed so as to be in contact with the top and bottom or the right and left of the power generation layer, and the minimum sintering temperature of the support layers is lower than the minimum sintering temperature of the power generation layer.