An analyzer comprising: a sample container transfer section (255, 355) including a plurality of specimen setting portions (255a, 355a, 255b, 355b) for holding a plurality of specimen containers of different types; wherein the plurality of specimen setting portions (255a, 355a, 255b, 355b) include a first specimen setting portion (255a, 355a), and a second specimen setting portion (255b, 355b) to be set with a specimen container of smaller volume than the specimen container to be set in the first specimen setting portion (255a, 355a); an aspiration section (21, 31) for aspirating the specimen from the specimen container set in the first specimen setting portion (255a, 355a) or the second specimen setting portion (255b, 355b); a presence detection section (26, 36) for detecting the presence of the specimen container set in at least one of the first and second specimen setting portions (255a, 255b, 355a, 355b); a unit cover (24, 34) having an opening (241a, 341a) and interiorly accommodating the aspiration section (21, 31) and the presence detection section (26, 36); and a controller for determining in which of the first and second specimen setting portions (255a, 355a, 255b, 355b) the specimen container is set based on the detection result of the presence detection section (26, 36), and controlling the operation of the aspiration section (21, 31), wherein: the analyzer further comprises: a moving assembly (255e, 255g, 255f, 355e, 355g, 355f) for moving linearly in a horizontal direction the sample container transfer section (255, 355) from priority specimen set position (620, 720) at which the specimen container is set to an aspiration position (600, 700) at which the specimen is aspirated by the aspiration section (21, 31), wherein the moving assembly (255e, 255g, 255f, 355e, 355g, 355f) is arranged to move the sample container transfer section (255, 355) through the opening (241a, 341a); wherein: the controller further controls the operation of the moving assembly (255e, 255g, 255f, 355e, 355g, 355f) so that the specimen container set in one of the first and second specimen setting portions (255a, 355a, 255b, 355b) is moved to the aspiration position (600, 700) based on the detection result of the presence detection section (26, 36), and wherein the controller is configured to control the operation of the sample container transfer section (255, 355) so that the sample container set in either the first specimen setting portion (255a, 355a) or the second specimen setting portion (255b, 355b) is moved to the aspiration position (600, 700) based on the detection result of the presence detection section (26, 36) irrespective of which specimen setting portion, the first specimen setting portion (255a, 355a) or the second specimen setting portion (255b, 355b), the sample container is set. a sample container transfer section (255, 355) including a plurality of specimen setting portions (255a, 355a, 255b, 355b) for holding a plurality of specimen containers of different types; wherein the plurality of specimen setting portions (255a, 355a, 255b, 355b) include a first specimen setting portion (255a, 355a), and a second specimen setting portion (255b, 355b) to be set with a specimen container of smaller volume than the specimen container to be set in the first specimen setting portion (255a, 355a); an aspiration section (21, 31) for aspirating the specimen from the specimen container set in the first specimen setting portion (255a, 355a) or the second specimen setting portion (255b, 355b); a presence detection section (26, 36) for detecting the presence of the specimen container set in at least one of the first and second specimen setting portions (255a, 255b, 355a, 355b); a unit cover (24, 34) having an opening (241a, 341a) and interiorly accommodating the aspiration section (21, 31) and the presence detection section (26, 36); and a controller for determining in which of the first and second specimen setting portions (255a, 355a, 255b, 355b) the specimen container is set based on the detection result of the presence detection section (26, 36), and controlling the operation of the aspiration section (21, 31), wherein: the analyzer further comprises: a moving assembly (255e, 255g, 255f, 355e, 355g, 355f) for moving linearly in a horizontal direction the sample container transfer section (255, 355) from priority specimen set position (620, 720) at which the specimen container is set to an aspiration position (600, 700) at which the specimen is aspirated by the aspiration section (21, 31), wherein the moving assembly (255e, 255g, 255f, 355e, 355g, 355f) is arranged to move the sample container transfer section (255, 355) through the opening (241a, 341a); wherein: the controller further controls the operation of the moving assembly (255e, 255g, 255f, 355e, 355g, 355f) so that the specimen container set in one of the first and second specimen setting portions (255a, 355a, 255b, 355b) is moved to the aspiration position (600, 700) based on the detection result of the presence detection section (26, 36), and wherein the controller is configured to control the operation of the sample container transfer section (255, 355) so that the sample container set in either the first specimen setting portion (255a, 355a) or the second specimen setting portion (255b, 355b) is moved to the aspiration position (600, 700) based on the detection result of the presence detection section (26, 36) irrespective of which specimen setting portion, the first specimen setting portion (255a, 355a) or the second specimen setting portion (255b, 355b), the sample container is set.