An intake passage structure for a turbocharger-equipped engine (1), wherein a supercharging passage (71) and an air relief passage (72) are provided inside a compressor case (21a). The air relief passage (72) has a nonlinear first passage (73) and a nonlinear second passage (74). The first passage (73) and the second passage (74) have air outflow ports (73a, 74a) that each open at an inner wall surface of a portion (71a) of the supercharging passage (71) that is on the upstream side of a compressor (21). The air outflow ports (73a, 74a) open at different circumferential-direction portions of the inner wall surface so as to overlap in the direction of a central axis of the upstream-side portion (71a).