To provide an extension type counter which is a wide counter eliminating a level difference and providing a sense of integrity.

A side cabinet, which is provided in a dressing room where a washbasin, a washing machine and the like are installed, is provided with a door plate 3 making the top face of a side cabinet body 1 serve as an upper counter surface 2, and the surface of which is made an obverse counter surface 4 equal as the upper counter surface 2, and having a foldable leg on the reverse side in the front opening portion 7 of the side cabinet body 1. The door plate 3 is turned upward to a horizontal position by a hinge connection 5, the surface counter side 4 of the door plate 3 and the upper counter surface 2 are held by a support leg 6 so as to be the same height.