  We have monitored a 3 deg2 area toward Serpens Main in the Pan-STARRS1 r, i,
and z bands from 2016 April to September. Light curves of more than 11,000
stars in each band were obtained, and 143 variables have been identified. Among
those, 119 variables are new discoveries, while 24 variables were previously
known. We present variability classes and periods of 99 stars. Of these, 81 are
located in the upper giant branch, displaying long periods, while the remaining
18 variables are pre-main-sequence objects with short periods. We also identify
eight eclipsing binary systems, including the known binary V0623 Ser, and
derive their physical parameters. According to a clustering analysis of Gaia
DR2 stars in the observed field, there are 10 variable members in Serpens Main,
where six members have been classified as young stellar objects in previous
studies. Here we provide color-magnitude and color-color diagrams for these
variables. The color variability of most variables in the color-magnitude
diagrams produce the expected displacements, while the movements of cluster
members point in different directions; this behavior may be associated with
accretion spots or circumstellar disks.
