To provide a semiconductor device which has high reliability against temperature change, and to provide a manufacturing method of the semiconductor device.

A semiconductor device according to this invention includes a cooler 101 having a main surface formed by a metal base 1, joined layers 3a, 3b fixed to the metal base 1 through junction layers 2a, 2b, insulation layers 4a, 4b fixed on the joined layers 3a, 3b and formed by an organic resin serving as a base material, metal layers 5a, 5b provided on the insulation layers 4a, 4b, and semiconductor elements 7a, 7b, 7c provided on the metal layers 5a, 5b. Laminates including the joined layers 3a, 3b, the insulation layers 4a, 4b, the metal layers 5a, 5b are divided for one or multiple semiconductor elements 7a, 7b, 7c and fixed on the metal base 1 through the junction layers 2a, 2b.