Steel plate having excellent hydrogen-induced cracking resistance and steel pipe for line pipe

Provided are a steel plate and a steel pipe that have excellent hydrogen-induced cracking resistance. Also provided are a steel plate and a steel pipe for which the HIC resistance thereof can be evaluated from the internal quality of a cast piece, without performing HIC tests. The steel plate having excellent hydrogen-induced cracking resistance fulfils prescribed C, Si, Mn, P, S, Al, Ca, N, and O content and comprises at least one element selected from the group consisting of a prescribed REM and Zr, with the remainder being iron and unavoidable impurities. The steel plate is characterized by: the Ca and S ratio (Ca/S) being at least 2.0; Ca, S, and O fulfilling (Ca - 1.25S) / O ≤ 1.80; and horizontal cracking not being present at the slab stage or the maximum opening thickness of horizontal cracking being no more than a threshold tθ and the threshold tθ being the maximum opening thickness of horizontal cracking at which hydrogen-induced cracking does not occur in a steel plate obtained by rolling the slab.