Transformer

A transformer comprising:

• a plurality of coils provided in a winding axis direction of the coils;
• a first cover and a second cover sandwiching the plurality of coils between the first and second covers from both sides in the winding axis direction;
• a first core and a second core sandwiching the first and second covers between the first and second cores from the both sides in the winding axis direction;
• a through-hole formed in at least one of a portion of the first cover and a portion of the second cover, the portion of the first cover facing the first core and one of the plurality of coils, the portion of the second cover facing the second core and another one of the plurality of coils;
• and
• a heat radiation member provided in the through-hole, the heat radiation member having thermal conductivity higher than thermal conductivity of the first cover and the second cover,
• wherein the through-hole penetrates a corresponding one of the first and second covers in a direction in which the plurality of coils, the first cover, the second cover, the first core, and the second core are stacked, the corresponding one of the first and second covers being provided with the through-hole, and
• the through-hole formed in the corresponding one of the first and second covers is filled with the heat radiation member, and thereby is sealed with the heat radiation member.