We report long-termed U BV RIRcIc photometry of the highly eccentric 12.04 day detached eclipsing binary V490 Sct (V =13.1, B9.5+A0, e = 0.40), which we use to determine its relative and absolute parameters. The absolute masses, radii, and temperatures are MA = 2.33±0.1 M , RA = 1.91±0.04 R , and TA = 9960±60 K for the primary and MB = 2.24±0.1 M , RB = 1.86±0.04 R , and TB = 9700±80 K for the secondary. The system displays a slow periastron advance that is dominated by general relativity (GR). Our measurement, ω = 0.86 deg century −1 , is 32% less then the expected rate, ω = 1.24 deg century −1 , which has an 83% contribution from GR. A comparison with current stellar evolution models shows a good match to the measured properties at an age of about 130 mln. years and Solar abundance. The photometrical parallax of the system π = 0.77 ± 0.02 mas, matches quite well the GAIA DR2 value, π = 0.76 ± 0.04 mas.