A drum type separation apparatus comprising: a liquid passage that allows a liquid mixed with a magnetic body (k) to pass therethrough, wherein a liquid surface is set in the liquid passage when the drum separation apparatus is in use; a rotary drum that is disposed such that a part of the rotary drum is exposed above the liquid surface in the liquid passage, the rotary drum being configured to transport the magnetic body (k) adsorbed on an outer peripheral surface thereof as the rotary drum rotates; and a magnet that is disposed on an inner side of the rotary drum, a squeezing roller at a position higher than the liquid surface, the squeezing roller being configured to separate out the liquid attached to the magnetic body (k) interposed between the outer peripheral surface of the rotary drum and the squeezing roller, and a scraper at a position higher than the liquid surface, the scraper being configured to scrape the magnetic body (k) from the rotary drum, wherein a magnetic force on a side lower than the liquid surface from an intersection position where the rotary drum and the liquid surface intersect each other is larger than a magnetic force on a side higher than the liquid surface from the intersection position, the magnet comprises three groups of permanent magnets (31, 32, 33) that have different magnetic forces from each other, are made of the same material, have almost the same area seen in a radial direction, and have thicknesses different from each other, the permanent magnets which have the smallest thickness and the smallest magnetic force are disposed in an angle range from a position where the squeezing roller faces the rotary drum to a tip position of the scraper, characterized in that the permanent magnets which have the second largest thickness and the second largest magnetic force are disposed in an angle range from an intersection position between the rotary drum and the liquid surface on an upstream side to the position facing the squeezing roller, the permanent magnets which have the largest thickness and the largest magnetic force are disposed lower than the liquid surface; the group of magnets having the second largest thickness and the second largest magnetic force includes a first magnet and a second magnet, which are disposed to be shifted respectively in a rotation direction and a reverse rotation direction of the rotary drum with respect to a line segment that connects a rotation center of the rotary drum and a rotation center of the squeezing roller to each other and are adjacent to each other, in a longitudinal section, and the line segment is shifted in the rotation direction from a midpoint of a line segment that connects a center of the first magnet and a center of the second magnet to each other. a liquid passage that allows a liquid mixed with a magnetic body (k) to pass therethrough, wherein a liquid surface is set in the liquid passage when the drum separation apparatus is in use; a rotary drum that is disposed such that a part of the rotary drum is exposed above the liquid surface in the liquid passage, the rotary drum being configured to transport the magnetic body (k) adsorbed on an outer peripheral surface thereof as the rotary drum rotates; and a magnet that is disposed on an inner side of the rotary drum, a squeezing roller at a position higher than the liquid surface, the squeezing roller being configured to separate out the liquid attached to the magnetic body (k) interposed between the outer peripheral surface of the rotary drum and the squeezing roller, and a scraper at a position higher than the liquid surface, the scraper being configured to scrape the magnetic body (k) from the rotary drum, wherein a magnetic force on a side lower than the liquid surface from an intersection position where the rotary drum and the liquid surface intersect each other is larger than a magnetic force on a side higher than the liquid surface from the intersection position, the magnet comprises three groups of permanent magnets (31, 32, 33) that have different magnetic forces from each other, are made of the same material, have almost the same area seen in a radial direction, and have thicknesses different from each other, the permanent magnets which have the smallest thickness and the smallest magnetic force are disposed in an angle range from a position where the squeezing roller faces the rotary drum to a tip position of the scraper, characterized in that the permanent magnets which have the second largest thickness and the second largest magnetic force are disposed in an angle range from an intersection position between the rotary drum and the liquid surface on an upstream side to the position facing the squeezing roller, the permanent magnets which have the largest thickness and the largest magnetic force are disposed lower than the liquid surface; the group of magnets having the second largest thickness and the second largest magnetic force includes a first magnet and a second magnet, which are disposed to be shifted respectively in a rotation direction and a reverse rotation direction of the rotary drum with respect to a line segment that connects a rotation center of the rotary drum and a rotation center of the squeezing roller to each other and are adjacent to each other, in a longitudinal section, and the line segment is shifted in the rotation direction from a midpoint of a line segment that connects a center of the first magnet and a center of the second magnet to each other.