A mold (1) includes an upper mold half (U) and a lower mold half (L). The mold (1) includes a gate (G), a pole vent pin (P), a support pin (S) and an intermediate vent pin (M). The support pin (S) has a latitude (.theta.s) of 45 degrees to 85 degrees. Each of the upper mold half (U) and the lower mold half (L) has at least three support pins (S). The intermediate vent pin (M) has a latitude (.theta.m) of 45 degrees to 85 degrees. Each of the upper mold half (U) and the lower mold half (L) has at least three intermediate vent pins (M). A difference between the latitude (.theta.m) of the intermediate vent pin (M) and the latitude (.theta.s) of the support pin (S) is equal to or smaller than 15 degrees. A clearance between the intermediate vent pin (M) and a pin hole (13) is 5 .mu.m to 50 .mu.m. By the mold (1), a cover having a thickness of 1.4 mm or less is formed.