A photodiode array (1, 30, 40, 50) in which a plurality of photodetector channels are formed on a substrate having a first semiconductor layer of a first conductivity type, with a light to be detected being incident to the plurality of photodetector channels, said photodiode array comprising: the substrate; an epitaxial semiconductor layer of a second conductivity type which is formed on the first semiconductor layer of the first conductivity type of the substrate and forms a pn junction at the interface with the first semiconductor layer, and also has a plurality of multiplication regions for avalanche multiplication of carriers produced by the incidence of the light to be detected so that each of the multiplication regions corresponds to each of the photodetector channels; a second semiconductor layer of the second conductivity type, having a higher impurity concentration than that of the epitaxial semiconductor layer, being formed at a light incident side of the epitaxial semiconductor layer, and consisting of a plurality of regions arranged corresponding to the multiplication regions, a plurality of resistors each of which has two ends (4a, 4b) and is provided for each of the photodetector channels; and a signal conductor comprising: a reading part for transmitting signals outputted from the photodetector channel; a connecting part for connecting between each resistor and the reading part; and for each of the photodetector channels, a channel surrounding part which is (i) arranged to surround the outer periphery of the respective photodetector channel, (ii) which is directly connected to the region of the second semiconductor layer in the respective photodetector channel, and (iii) which is connected to one end of the resistor in the respective photodetector channel, wherein each of the plurality of resistors is electrically connected to the epitaxial semiconductor layer via one end of the resistor and via the channel surrounding part in the respective photodetector channel; and is connected to the reading part of the signal conductor via the connecting part and via the other end of the resistor. the substrate; an epitaxial semiconductor layer of a second conductivity type which is formed on the first semiconductor layer of the first conductivity type of the substrate and forms a pn junction at the interface with the first semiconductor layer, and also has a plurality of multiplication regions for avalanche multiplication of carriers produced by the incidence of the light to be detected so that each of the multiplication regions corresponds to each of the photodetector channels; a second semiconductor layer of the second conductivity type, having a higher impurity concentration than that of the epitaxial semiconductor layer, being formed at a light incident side of the epitaxial semiconductor layer, and consisting of a plurality of regions arranged corresponding to the multiplication regions, a plurality of resistors each of which has two ends (4a, 4b) and is provided for each of the photodetector channels; and a signal conductor comprising: a reading part for transmitting signals outputted from the photodetector channel; a connecting part for connecting between each resistor and the reading part; and for each of the photodetector channels, a channel surrounding part which is (i) arranged to surround the outer periphery of the respective photodetector channel, (ii) which is directly connected to the region of the second semiconductor layer in the respective photodetector channel, and (iii) which is connected to one end of the resistor in the respective photodetector channel, wherein each of the plurality of resistors is electrically connected to the epitaxial semiconductor layer via one end of the resistor and via the channel surrounding part in the respective photodetector channel; and is connected to the reading part of the signal conductor via the connecting part and via the other end of the resistor. a reading part for transmitting signals outputted from the photodetector channel; a connecting part for connecting between each resistor and the reading part; and for each of the photodetector channels, a channel surrounding part which is (i) arranged to surround the outer periphery of the respective photodetector channel, (ii) which is directly connected to the region of the second semiconductor layer in the respective photodetector channel, and (iii) which is connected to one end of the resistor in the respective photodetector channel, wherein each of the plurality of resistors is electrically connected to the epitaxial semiconductor layer via one end of the resistor and via the channel surrounding part in the respective photodetector channel; and is connected to the reading part of the signal conductor via the connecting part and via the other end of the resistor.