An engine muffler (10; 10A; 10B) comprising: a cylindrical muffler body; and at least one partition plate (30, 40) partitioning an interior of the muffler body in a longitudinal direction of the muffler body into a plurality of expansion chambers (91, 92, 93), the muffler body being constructed of a plurality of divided muffler body members (21, 22, 23) divided from each other in the longitudinal direction at a position of the partition plate (30, 40), a gap (Cr1, Cr2) being provided between opposed end portions (21a, 22a, 22c, 23a) of the plurality of divided muffler body members (21, 22, 23), the partition plate (30, 40) having an annular section (31, 41) held in fitting engagement with an inner peripheral surface of at least one of the opposed end portions (21a, 22a, 22c, 23a) of the plurality of divided muffler body members (21, 22, 23), the partition plate (30, 40) being disposed in such a manner as to close the gap (Cr1, Cr2), the opposed end portions (21a, 22a, 22c, 23a) of the plurality of divided muffler body members (21, 22, 23) being welded, from a radially outward direction of the muffler body, to an outer peripheral surface (31a, 41a) of the annular section (31, 41) along respective entire perimeters thereof, characterized in that the plurality of expansion chambers comprise first, second and third expansion chambers (91, 92, 93) sequentially arranged in the longitudinal direction, and the at least one partition plate comprises first and second partition plates (30, 40), the first partition plate partitioning between the first expansion chamber and the second expansion chamber, the second partition plate partitioning between the second expansion chamber and the third expansion chamber, and which further comprises a communication pipe extending between the first partition plate and the second partition plate, the communication pipe having a catalyst layer provided therein and having a longitudinally-halfway portion communicating with the second expansion chamber, the communication pipe having one end portion communicating with the first expansion chamber and joined to the first partition plate along an entire perimeter thereof, the communication pipe having another end portion slidably fitted in a through-hole formed in the second partition plate, the other end portion of the communication pipe and the through-hole being covered with a cap from a side of the third expanded chamber, the cap being joined to the second partition plate in a sealed condition. a cylindrical muffler body; and at least one partition plate (30, 40) partitioning an interior of the muffler body in a longitudinal direction of the muffler body into a plurality of expansion chambers (91, 92, 93), the muffler body being constructed of a plurality of divided muffler body members (21, 22, 23) divided from each other in the longitudinal direction at a position of the partition plate (30, 40), a gap (Cr1, Cr2) being provided between opposed end portions (21a, 22a, 22c, 23a) of the plurality of divided muffler body members (21, 22, 23), the partition plate (30, 40) having an annular section (31, 41) held in fitting engagement with an inner peripheral surface of at least one of the opposed end portions (21a, 22a, 22c, 23a) of the plurality of divided muffler body members (21, 22, 23), the partition plate (30, 40) being disposed in such a manner as to close the gap (Cr1, Cr2), the opposed end portions (21a, 22a, 22c, 23a) of the plurality of divided muffler body members (21, 22, 23) being welded, from a radially outward direction of the muffler body, to an outer peripheral surface (31a, 41a) of the annular section (31, 41) along respective entire perimeters thereof, characterized in that the plurality of expansion chambers comprise first, second and third expansion chambers (91, 92, 93) sequentially arranged in the longitudinal direction, and the at least one partition plate comprises first and second partition plates (30, 40), the first partition plate partitioning between the first expansion chamber and the second expansion chamber, the second partition plate partitioning between the second expansion chamber and the third expansion chamber, and which further comprises a communication pipe extending between the first partition plate and the second partition plate, the communication pipe having a catalyst layer provided therein and having a longitudinally-halfway portion communicating with the second expansion chamber, the communication pipe having one end portion communicating with the first expansion chamber and joined to the first partition plate along an entire perimeter thereof, the communication pipe having another end portion slidably fitted in a through-hole formed in the second partition plate, the other end portion of the communication pipe and the through-hole being covered with a cap from a side of the third expanded chamber, the cap being joined to the second partition plate in a sealed condition.