Medium stacking apparatus and postprocessing apparatus

A medium stacking apparatus comprising:

• a placement section having a placement area in which one or more media that recorded medium are placed;
• an alignment section that aligns downstream, leading edges, in a transport direction, of the media that were transported to the placement section;
• a transport section that transports, to the alignment section, the media that were transported to the placement section;
• and
• a moving section that moves the media stacked on the placement section in a width direction, the width direction intersecting the transport direction, wherein
• the alignment section includes
• a first alignment surface having a first friction coefficient for contact with the media, and
• a second alignment surface having a second friction coefficient for contact with the media, the second friction coefficient being lower than the first friction coefficient,
• the first alignment surface and the second alignment surface are side by side in the width direction, and
• the second alignment surface is positioned upstream of the first alignment surface in the transport direction and closer to a center of the placement area in the width direction than the first alignment surface is.