A cartridge comprising: a housing; a storage medium having an electrical contact surface; and a holder movable relative to the housing, the holder comprising: a first holder member having a pawl portion (52; 53) and configured to hold the electrical contact surface; and a second holder member comprising a corner portion (62; 63) with which the pawl portion (52; 53) is engageable, the second holder member having a through-hole (67; 68) through which an engagement part (522; 532) of the pawl portion (52; 53) engaging with the corner portion (62; 63) is accessible from outside the second holder member in a state where the pawl portion (52; 53) engages with the corner portion (62; 63); a holder cover movable together with the housing, the holder cover positioned at an outer surface of the housing, the holder cover being configured to hold the second holder member between the outer surface of the housing and the holder cover in a state where the second holder member is movable relative to the housing and the holder cover, wherein the pawl portion (52; 53) comprises: an arm part (521; 531) extending in a first direction crossing the electrical contact surface; and a hook part (522; 532) protruding from a distal end of the arm part (521; 531) in a second direction crossing the first direction, the hook part (522; 532) being configured to engage with the corner portion (62; 63), and characterized in that the second holder member comprises a first boss extending in the second direction, and wherein the through-hole (67; 68) is a hole penetrating the first boss in the second direction toward the hook part (522; 532), wherein the holder cover has a cover hole into which the first boss is inserted, and wherein the first boss is movable in the first direction inside the cover hole. a housing; a storage medium having an electrical contact surface; and a holder movable relative to the housing, the holder comprising: a first holder member having a pawl portion (52; 53) and configured to hold the electrical contact surface; and a second holder member comprising a corner portion (62; 63) with which the pawl portion (52; 53) is engageable, the second holder member having a through-hole (67; 68) through which an engagement part (522; 532) of the pawl portion (52; 53) engaging with the corner portion (62; 63) is accessible from outside the second holder member in a state where the pawl portion (52; 53) engages with the corner portion (62; 63); a holder cover movable together with the housing, the holder cover positioned at an outer surface of the housing, the holder cover being configured to hold the second holder member between the outer surface of the housing and the holder cover in a state where the second holder member is movable relative to the housing and the holder cover, a first holder member having a pawl portion (52; 53) and configured to hold the electrical contact surface; and a second holder member comprising a corner portion (62; 63) with which the pawl portion (52; 53) is engageable, the second holder member having a through-hole (67; 68) through which an engagement part (522; 532) of the pawl portion (52; 53) engaging with the corner portion (62; 63) is accessible from outside the second holder member in a state where the pawl portion (52; 53) engages with the corner portion (62; 63); a holder cover movable together with the housing, the holder cover positioned at an outer surface of the housing, the holder cover being configured to hold the second holder member between the outer surface of the housing and the holder cover in a state where the second holder member is movable relative to the housing and the holder cover, wherein the pawl portion (52; 53) comprises: an arm part (521; 531) extending in a first direction crossing the electrical contact surface; and a hook part (522; 532) protruding from a distal end of the arm part (521; 531) in a second direction crossing the first direction, the hook part (522; 532) being configured to engage with the corner portion (62; 63), an arm part (521; 531) extending in a first direction crossing the electrical contact surface; and a hook part (522; 532) protruding from a distal end of the arm part (521; 531) in a second direction crossing the first direction, the hook part (522; 532) being configured to engage with the corner portion (62; 63), and characterized in that the second holder member comprises a first boss extending in the second direction, and wherein the through-hole (67; 68) is a hole penetrating the first boss in the second direction toward the hook part (522; 532), wherein the holder cover has a cover hole into which the first boss is inserted, and wherein the first boss is movable in the first direction inside the cover hole.