Officers with the Police Department's Covert Response Unit found and arrested the suspect at about 8:10 p.m. He will be booked into Santa Clara County Jail, police Officer Albert Morales said.
The suspect's name and how he was arrested has not been released.
Most of the fires were set between 2 a.m. and 6 a.m. last Wednesday, Thursday and Friday between Santa Clara Street and William Street and between 17th Street and 33rd Street, according to fire officials.
Two more fires were reported Sunday morning in the same area.