The invention discloses a linear generator, and the linear generator comprises a primary side and a secondary side; the primary side comprises a primary yoke, a coil and at least one permanent magnetarray; N and S poles of permanent magnets in the permanent magnet array are alternately and uniformly arranged; the primary yoke is provided with a primary convex part, and the coil is sleeved on theprimary convex part or the primary yoke; the permanent magnet array is arranged on the primary yoke; the secondary comprises a secondary yoke and secondary teeth; the secondary teeth are of flat-plate-shaped and uniformly-toothed finger-shaped structures, the tooth pitch of the secondary teeth is equal to non-zero even-number times of the polar pitch of the permanent magnet, and a gap exists between the secondary yoke and the primary protruding part and is a first air gap; the permanent magnet array and the secondary teeth are arranged on the same plane or the whole column of permanent magnetsare arranged below the secondary teeth, and a gap exists between the permanent magnet array and the secondary teeth and is a second air gap; the secondary teeth move on a plane, so a current is generated in the coil through changes of a magnetic circuit and magnetic flux. The invention provides the novel linear generator which is small in size and simple in structure.