An image heating device for heating an image formed on a recording material, comprising: a heater, the heater includes, a substrate; a first conductive element provided on the substrate along a longitudinal direction of the substrate; a second conductive element provided on the substrate along the longitudinal direction at a position different from the first conductive element in a widthwise direction of the substrate; and a heat generating resistor provided between the first conductive element and the second conductive element, and showing a positive temperature characteristic of resistance, which generates heat when power is supplied via the first conductive element and the second conductive element, characterized in that a plurality of heating blocks each of which includes a set of the first conductive element, the second conductive element, and the heat generating resistor is provided in the longitudinal direction, and power control of a heating block (302-1, 302-3) which is positioned remote from a conveyance reference position is arranged to be performed independently of a heating block which is positioned at a position including the conveyance reference position, and the device further comprises a first temperature detecting element configured to detect a temperature of the heating block which is positioned at the position including the conveyance reference position, a second temperature detecting element (TH2, TH3) configured to detect a temperature of the heating block (302-1, 302-3) which is positioned remote from the conveyance reference position, and a third temperature detecting element configured to detect a temperature of, in the longitudinal direction of the substrate, an end portion of the heating block which is positioned at the position including the conveyance reference position. a heater, the heater includes, a substrate; a first conductive element provided on the substrate along a longitudinal direction of the substrate; a second conductive element provided on the substrate along the longitudinal direction at a position different from the first conductive element in a widthwise direction of the substrate; and a heat generating resistor provided between the first conductive element and the second conductive element, and showing a positive temperature characteristic of resistance, which generates heat when power is supplied via the first conductive element and the second conductive element, characterized in that a plurality of heating blocks each of which includes a set of the first conductive element, the second conductive element, and the heat generating resistor is provided in the longitudinal direction, and power control of a heating block (302-1, 302-3) which is positioned remote from a conveyance reference position is arranged to be performed independently of a heating block which is positioned at a position including the conveyance reference position, and the device further comprises a first temperature detecting element configured to detect a temperature of the heating block which is positioned at the position including the conveyance reference position, a second temperature detecting element (TH2, TH3) configured to detect a temperature of the heating block (302-1, 302-3) which is positioned remote from the conveyance reference position, and a third temperature detecting element configured to detect a temperature of, in the longitudinal direction of the substrate, an end portion of the heating block which is positioned at the position including the conveyance reference position.