To provide a miniaturized board accommodation type transformer that secures earthquake-resistant strength in a transformer body and does not use any earthquake-resistant fixtures except the transformer body, in a board accommodation type transformer requiring earthquake-resistant strength.

In the board accommodation type transformer that is equipped with a core 2 and a coil 1 that is wound around the core 2, and has earthquake- resistant performance, the core 2 is pressed down by a core presser plate where a core section presser plate 3 and a yoke section presser plate 32 are welded in one piece. The core presser plate has a U-shaped section. The core presser plate is reinforced by a reinforcement stay. The reinforcement stay is welded and fixed to a transformer body base section.