To solve a problem wherein, when a condensation seal is used for a seal material of a base and a cover of an on-vehicle electronic apparatus, hardening thereof is slow and productivity is degraded.

This on-vehicle electronic apparatus includes a base for dissipating heat from an electronic component and installing a circuit board thereon. The on-vehicle electronic apparatus for installing, on the base, a board for forming the circuit board by mounting the electronic component thereon is structured such that, in a seal surface of the base and the cover, a through-hole is formed on the cover, and a seal material runs off therefrom.