A compressor includes plural first vanes provided on a shroud side of a diffuser path, and plural second vanes provided on positions of a hub side opposed to the first vanes. The compressor also includes a slide vane mechanism that projects the second vanes into and draws in the second vanes from the diffuser path via the slits of the hub side wall part plate according to a load of the compressor. When the slide vane mechanism projects the second vanes into the diffuser path, end faces of the first vanes and end faces of the second vanes are opposed to each other at the vicinity of the center of the diffuser path.