Randomness plays a vital role in numerous applications, including simulation, cryptography, distributed systems, and gaming. Consequently, extensive research has been conducted to generate randomness. One such method is to design a decentralized random number generator (DRNG), a protocol that enables multiple participants to collaboratively generate random outputs that must be publicly verifiable. However, existing DRNGs are either not secure against quantum computers or depend on the random oracle model (ROM) to achieve security. In this paper, we design a DRNG based on lattice-based publicly verifiable secret sharing (PVSS) that is post-quantum secure and proven secure in the standard model. Additionally, our DRNG requires only two rounds of communication to generate a single (pseudo)random value and can tolerate up to any \(t < n/2\) dishonest participants. To our knowledge, the proposed DRNG construction is the first to achieve all these properties.