PURPOSE: To obtain a magnetic field generator having a structure enabling an accurate magnetization of permanent magnet blocks by a method wherein a small block composing permanent magnet blocks of the side which is not parallel to or is not at a right angle to a direction of a uniform magnetic field is composed of the blocks magnetized in a direction parallel to the side and the blocks magnetized in a direction being at a right angle to the side.

CONSTITUTION: A magnetic field generator is formed by bonding permanent magnet blocks 11a - h with an epoxy-group adhesive agent. In an inner space 12 of a cylindrical body, a uniform magnetic filed distribution can be obtained in a direction shown by an arrow 13 in a plane vertical to an axis of the cylindrical body. Among the permanent magnet blocks 11a, 11b....11h, permanent magnet blocks 11a, 11e which form a side being at a right angle to a magnetic field direction, and the permanent magnet blocks 11c, 11g which form a side parallel to that direction are made a permanent magnet independently and are magnetized to the same strength. Permanent magnet small blocks 15a are magnetized in a parallel direction to the side of the small blocks, whereas permanent magnet small blocks 15b are magnetized in a direction being at right angles to the side of the small blocks and their magnetization strengths are equal.